exactly the same over here
when a i was working arround 96
in a shop that represented Adcom and Nakamichi in athens i got a note from the owner that GFA 5800 repairs should be done with in 2 hours or Nakamichi cr2E should be done in one hour .....or sunfire true sub should also done in similar time margin
i only lasted a few month there .....and like you OS i explain to my costumers that it is coslty and will take time to make a good device alive again ....
still in greece prices are very low and for example any normal vintage hifi amplifier will go out of my shop after what we call minimum upgrade with a cost of 100-150 euros .....
upgrade includes
banks recaped
all unit recaped
most ceramics removed
cleaning, resoldering
sometimes rewiring
sometimes A/B speakers switch removal
fresh thermopaste / nicassil insulators
multiturns in ofsset or bias
and often some of suspect resistors remmoved
relocation of zobel....
after all that we can go farther but then its costumer's thing if he wants to go more like replacing plugs and so on....
all costumers also get a CD with performance figures and of course we keep records of that for future reference
ostripper said:
NTE sucks..I built your c200 with them , it blew
replaced with on semi stock and it still works. Down with
NTE (overpriced floorsweepings ,like radioshack semi's).
I now do all 4 of the major repair services (receivers , monitors,
tv, and PC's) but my real passion is audio. Even if it means
less profit and more time , I do not want to see the unit again.
90 days is too short for a good reputation, even if it would be
more profitable. So I will keep a classic amp with me for a while
(week) ,abuse it thoroughly in the real world.
I worked for tandy (radio shack) as a receiver tech and they
did not want to hear any music from my corner.. just run
a sine into a test load for 1 minute. They even told me to underbias the OP to make sure I got the 90 days or I
would have to fix it again for free.
OS
when a i was working arround 96
in a shop that represented Adcom and Nakamichi in athens i got a note from the owner that GFA 5800 repairs should be done with in 2 hours or Nakamichi cr2E should be done in one hour .....or sunfire true sub should also done in similar time margin
i only lasted a few month there .....and like you OS i explain to my costumers that it is coslty and will take time to make a good device alive again ....
still in greece prices are very low and for example any normal vintage hifi amplifier will go out of my shop after what we call minimum upgrade with a cost of 100-150 euros .....
upgrade includes
banks recaped
all unit recaped
most ceramics removed
cleaning, resoldering
sometimes rewiring
sometimes A/B speakers switch removal
fresh thermopaste / nicassil insulators
multiturns in ofsset or bias
and often some of suspect resistors remmoved
relocation of zobel....
after all that we can go farther but then its costumer's thing if he wants to go more like replacing plugs and so on....
all costumers also get a CD with performance figures and of course we keep records of that for future reference
Hi ostripper,
Everyone should know my feelings on ECG/NTE trash. If I see one of these in any repair, they on the estimate as a must do. The shop where that part came from is them marked as a hack shop.
-Chris
Everyone should know my feelings on ECG/NTE trash. If I see one of these in any repair, they on the estimate as a must do. The shop where that part came from is them marked as a hack shop.
You are one of the few good shops I mentioned then. You are right also, a returned unit is a financial disaster. Better to spend extra time now - even at no charge, then to have to redo the entire job. Plus what you were supposed to do.
I disagree with you on that. I warranty my workmanship for years if I see a unit back, but there are some abuses and the 90 day warranty saves me from those people. Parts such as lamps and laser heads may fail early, nothing you can do. But that is not my fault and I will give the customer a huge break on the price. My point here is that I shouldn't be out money, and I am doing the job over with no profit. My goal is to be honest and reasonable with a customer. Just treat them in a way I'd like to be treated.
Yeah. Some of the shops I worked in were like that too. Barring a design fault, normal setup will not increase service calls. This is just for those people who stack everything up with no ventilation.
-Chris
Hi Sakis,
Perceived value for service has always been an issue. Your customer can not see your work and there is always someone who will work cheaper. Don't play that game. Do really good work and charge reasonable money for it. The better customers will come to you. Your service is often less expensive in the long run, and the performance of the unit is better. You don't need the price fixated customer. Besides, some repairs I do for free or even just $30 if they are quick ones. Good doesn't have to be expensive.
-Chris
many shops here are like that also. That is why workmanship can be terrible and stupid mistakes are made. When I ran my shop, I paid my guys more labour just to get warranty service done. I would pay them for the time and absorb the loss. At least Nakamichi and Adcom were reasonable and would pay extra for those tougher jobs. The main focus was to get the unit out without cosmetic damage, and properly repaired. Warranty service is often done at a loss, unless you can win on some you get good at. You lose on the repair but the manuals and customer referrals more than make it up. Once you deal with a customer properly, you have a customer for life. I did well with that.
Perceived value for service has always been an issue. Your customer can not see your work and there is always someone who will work cheaper. Don't play that game. Do really good work and charge reasonable money for it. The better customers will come to you. Your service is often less expensive in the long run, and the performance of the unit is better. You don't need the price fixated customer. Besides, some repairs I do for free or even just $30 if they are quick ones. Good doesn't have to be expensive.
-Chris
That is where sherlock holmes comes in, If the customer spilled
a drink in the unit, I will know it and 90 days won't even apply.
A frank discussion and maybe even a visual review of the unit
is in order.
In the case of a older unit ,if they want to be cheap and NOT
upgrade/recap as advised , I might not give 90 and discuss why.
The same goes for the other stuff, Heat ,old caps are the same
on the CRT's... any power equiptment. You ESR the caps and
even as they still work , they are far from spec. So maybe
you get accused of replacing good components (still good
visiblely) but in 30 or 60 days the bad ESR cap will be toast
(especially in a CRT SMPS). Same goes for amps under heavy
use (high ripple environment).
I had a batch of gateway 17" flatscreens and 3 worked,
7 did not.. the same 2-1uf 50V caps were bad on the 7 ,but
I bought 20- 1u/100v high esr replacements and did 'em all.
I own 2 and the other 8 are still being happily surfed on after
a year.
A sliding warranty is what I have used, especially for classic
equiptment. 90 days is for the newer HT receivers (blew the left
front, etc.) , but those I rarely see back.
As far as 90 being too short for a good reputation..I meant
that I would like my repairs to last far longer than 90 to
instill faith from my clients.
OS
Hi ostripper,
We had a rule in our shop. If "it" has a handle on it, we don't fix "it", except the Revox machines. Cut the aggravation level way down.
-Chris
That we both agree on. But you are at a disadvantage because of the new stuff you work on. Once old stuff is repaired, they typically run for another 10 + years. I haven't got time in my life for monitors and VCRs. Especially not those customers. I've noticed there is almost nothing worse than a TV down with a young family. Computers are another problem area. The fault may be clear, and the cause - to you. It's getting some people to accept the truth. They just simply don't want to pay and will pin the cost on whoever they can. That's why I didn't service any video stuff at all. Just audio.
We had a rule in our shop. If "it" has a handle on it, we don't fix "it", except the Revox machines. Cut the aggravation level way down.
-Chris
VCR's for the last 5 years have not been economically repairable.
a head assembly costs more than a new unit. Same for most
CD/DVD players .. laser assembly costs more than a new unit.
they don't make VCR's anymore (3 months ago ,JVC was last)
and a florida company 1 month ago was the last to sell the tapes.
With most CD players,
the only way to make any money is to let the units pile up,
identify the good assemblies , and build working ones
from the "ashes" for resale as used equiptment.
Flat screens are cool, 99% are SMPS (switching tranny or
caps)related. 1-2 $ parts equals 75-100$ repair..10 minutes.
even 15" flatties go for 150+ so good demand.
The few classic amps I've done were owned by audiophiles
who loved their sound and would pay a premium price for
restoration.They got their money's worth, regreased/
replaced all op's,(IF blown bought matched ones.)
full recap, biasing after equilibrium (couldn't do that at tandy,
underbias "trick" to save time.) board wash, even cosmetic touchup if required.
The walmart/Best buy (no more circuit city
) HT recieverrepair is still profitable as most of the 5/7 channel units are
IC driven darlington pairs, In fact, most use sanken MN-XXX
devices making stock a breeze. The IC's they use don't
require idle adjustment , just original components. (or they have
integrated bias chains - sanken)
The only way I can afford to do audio restoration is by the
bounty of the flatscreen/PC business. In tennessee cheap Walmart HT systems rule and we lack audiophiles.(seems to
be more in AU /CA /europe).
Hi ostripper,
That's grim.
That's also the reason I sold my shop. I was positioned really well in the market. Audio only. Mostly "mid fi" and high end service. The recording studio and live sound markets kept us afloat. We didn't do much mass marketing stuff.
As I was selling the place, "George" * got the brilliant idea of increasing the volume with junk. So, he picked up Sharp. The LCD projectors were about the only money maker after buying the required gear. So, he went from lower volume high paying good stuff warranty to tons of low end, low paying warranty. Of course, with the much increased paperwork and record keeping. This also placed us in a more competitive market (all the TV shops and other hackers).
His service methods killed all the really good contracts except for McIntosh (the reps were his personal friends).
What a great business plan. I'm glad I wasn't around for that.
-Chris
* - George. The guy that bought my shop by forcing me out and ripping me off for thousands. Where the market has gone couldn't have happened to a nicer guy.
My apologies to all the hard working, intelligent people who are still in that business for the love of audio.
That's grim.
That's also the reason I sold my shop. I was positioned really well in the market. Audio only. Mostly "mid fi" and high end service. The recording studio and live sound markets kept us afloat. We didn't do much mass marketing stuff.
As I was selling the place, "George" * got the brilliant idea of increasing the volume with junk. So, he picked up Sharp. The LCD projectors were about the only money maker after buying the required gear. So, he went from lower volume high paying good stuff warranty to tons of low end, low paying warranty. Of course, with the much increased paperwork and record keeping. This also placed us in a more competitive market (all the TV shops and other hackers).
His service methods killed all the really good contracts except for McIntosh (the reps were his personal friends).
What a great business plan. I'm glad I wasn't around for that.
-Chris
* - George. The guy that bought my shop by forcing me out and ripping me off for thousands. Where the market has gone couldn't have happened to a nicer guy.
My apologies to all the hard working, intelligent people who are still in that business for the love of audio.
FIXED
allright doubters, so i replaced q711 (2sa977) and q712 (2sc2257) with a 2SA1210/2SC2912 pair by Sanyo. Q711 did turn out to be busted after i got it off the board and tested it. Matching parts turned out to be kind of a moot point since they all tested out within 5%.
i also replaced q714 (2sa968b) and q713 (2sc2238b), after q714 turned out to be busted too. i used 2sb861 for q14 and 2sd1138 for q13. again, they all matched.
so at that point, i had the good right channel out with the <previously> bad left channel and started making resistance comparisons as per Sakis' suggestion. all the points i tested were comparable and i felt good about powering up the board.
put it back together, turned it on and held my breath for about 2 seconds until the protection relay clicked. everything was mellow. i let it sit to see if anything heated up excessively. when nothing did, i connected a source and it sounded GREAT!
i bought enough elna silmic ii's to recap both boards and the protection circuit, but i think i'll put that off until i don't feel as lucky as i do now to have it working.
thanks again for the help guys, reluctant or otherwise.
i'll be starting a new thread soon for fixing my 1300DC. in this case i'm blameless. some "tech" got to it before i ever owned it and it's never sounded good.
allright doubters, so i replaced q711 (2sa977) and q712 (2sc2257) with a 2SA1210/2SC2912 pair by Sanyo. Q711 did turn out to be busted after i got it off the board and tested it. Matching parts turned out to be kind of a moot point since they all tested out within 5%.
i also replaced q714 (2sa968b) and q713 (2sc2238b), after q714 turned out to be busted too. i used 2sb861 for q14 and 2sd1138 for q13. again, they all matched.
so at that point, i had the good right channel out with the <previously> bad left channel and started making resistance comparisons as per Sakis' suggestion. all the points i tested were comparable and i felt good about powering up the board.
put it back together, turned it on and held my breath for about 2 seconds until the protection relay clicked. everything was mellow. i let it sit to see if anything heated up excessively. when nothing did, i connected a source and it sounded GREAT!
i bought enough elna silmic ii's to recap both boards and the protection circuit, but i think i'll put that off until i don't feel as lucky as i do now to have it working.
thanks again for the help guys, reluctant or otherwise.
i'll be starting a new thread soon for fixing my 1300DC. in this case i'm blameless. some "tech" got to it before i ever owned it and it's never sounded good.
Re: FIXED
Glad to see you got it back in shape.
I have a 300DC sitting in a box in pieces that was worked
on by some hack. I haven't as of yet had time
to go through and reassemble it. All of the electronics are there
but a few of the hardware pieces are missing. The poor beast has NTE cancer, meaning the boards are infested or "ate up" with them. The amp boards will need a total rework to deal with that disease and any other nasties that may lurk.
mechanicalman said:
Glad to see you got it back in shape.
I have a 300DC sitting in a box in pieces that was worked
on by some hack. I haven't as of yet had time
to go through and reassemble it. All of the electronics are there
but a few of the hardware pieces are missing. The poor beast has NTE cancer, meaning the boards are infested or "ate up" with them. The amp boards will need a total rework to deal with that disease and any other nasties that may lurk.
Hi mechanicalman,
Good for you, I am happy you did get it running.
When I judge whether someone should attempt to service their unit or not, I go on past experience and what I can see of the person's technical abilities.
Now, some caveats. You say it's now working, okay. However there are some things that may be an issue down the road, or are issues just waiting to show up.
Do you have any idea what the bias current is? Do you have any idea whether the bias current is stable or not?
Do you know what the DC offset is and if that is stable? Do you have any idea how much distortion there is now. Note, I don't care if you say that it sounds "good enough for you", because I already know you wouldn't be able to tell the difference between channels unless there was something seriously wrong. Distortion measurements also tell us if the amplifier is working properly. Another clue in our arsenal of circuit checks.
Do you know if you over tightened any transistors? My bet is that you did, no comment on you. You just have no training and so no feel or equipment to measure this. BTW, this is more important than you think. Did you use new mica insulators where required and fresh thermal compound (and not "Arctic Silver"!)? This is critical.
Lastly, did you damage any traces at all? Did you remove the solder flux from your own soldering?
If you have messed up any of these things, you have illustrated why you should not have attempted to service this amp.
Now, onto the 1300.
You are not blameless if your workmanship is not up to the task. At that point, you will be just as much to blame as the previous technician. Previous bad work never excuses you from the same.
"No one single snowflake in an avalanche ever feels responsible"
I am very disappointed that you decided to work on these, only because of the high caliber of the equipment. That's why the resale value is so high. If you were working on simpler amplifiers that were not worth as much, my objections would be far, far less. But you have determined to do something that you do not understand and I find it's very sad that really nice equipment was risked to satisfy your ego.
I've said this to every technician I have ever trained, and this is true. BTW, I have been much easier on you than the people I have trained as technicians. There is no "nice" or "not nice", there is only right or wrong.
"Just because an item operates does not mean that it's fixed. Something is only fixed after the mechanical work has been done properly and the item has been adjusted or confirmed to be working properly to original specifications."
-Chris
Good for you, I am happy you did get it running.
When I judge whether someone should attempt to service their unit or not, I go on past experience and what I can see of the person's technical abilities.
Now, some caveats. You say it's now working, okay. However there are some things that may be an issue down the road, or are issues just waiting to show up.
Do you have any idea what the bias current is? Do you have any idea whether the bias current is stable or not?
Do you know what the DC offset is and if that is stable? Do you have any idea how much distortion there is now. Note, I don't care if you say that it sounds "good enough for you", because I already know you wouldn't be able to tell the difference between channels unless there was something seriously wrong. Distortion measurements also tell us if the amplifier is working properly. Another clue in our arsenal of circuit checks.
Do you know if you over tightened any transistors? My bet is that you did, no comment on you. You just have no training and so no feel or equipment to measure this. BTW, this is more important than you think. Did you use new mica insulators where required and fresh thermal compound (and not "Arctic Silver"!)? This is critical.
Lastly, did you damage any traces at all? Did you remove the solder flux from your own soldering?
If you have messed up any of these things, you have illustrated why you should not have attempted to service this amp.
Now, onto the 1300.
An improperly serviced amplifier has further challenges in addition to the previous comments. Be extremely careful with the traces and do not apply any pressure on them at all.
You are not blameless if your workmanship is not up to the task. At that point, you will be just as much to blame as the previous technician. Previous bad work never excuses you from the same.
"No one single snowflake in an avalanche ever feels responsible"
I am very disappointed that you decided to work on these, only because of the high caliber of the equipment. That's why the resale value is so high. If you were working on simpler amplifiers that were not worth as much, my objections would be far, far less. But you have determined to do something that you do not understand and I find it's very sad that really nice equipment was risked to satisfy your ego.
I've said this to every technician I have ever trained, and this is true. BTW, I have been much easier on you than the people I have trained as technicians. There is no "nice" or "not nice", there is only right or wrong.
"Just because an item operates does not mean that it's fixed. Something is only fixed after the mechanical work has been done properly and the item has been adjusted or confirmed to be working properly to original specifications."
-Chris
anatech said:
When it comes to transistors there really is no need to use
their garbage. Especially with all of the current products available from different manufacturers. One of the very few times I really made an exception to that is on an occasion when I had a Marantz receiver
come in with a blown HA1156. I couldn't find one anywhere so
I bit the bullet and used an NTE 801.
Hi Glen,
The one thing that was okay with ECG or NTE were ICs like that. It's not like they could substitute those for something else. It's just the prices were sooooo high.
I have no problem with ECG/NTE when it comes to an obsolete special function IC.
Why is it that the MPX ICs have a higher failure rate than normal? I noticed that within a month of my first job, many, many years ago.
-Chris
Edit:
Don't throw it out Glen. If you tire of it, please let me know as I love a challenge. Right now, I'm extremely poor and can't afford anything right away.
-Chris
The one thing that was okay with ECG or NTE were ICs like that. It's not like they could substitute those for something else. It's just the prices were sooooo high.
I have no problem with ECG/NTE when it comes to an obsolete special function IC.
Why is it that the MPX ICs have a higher failure rate than normal? I noticed that within a month of my first job, many, many years ago.
-Chris
Edit:
Heart breaking.
The mark of a hacker, what's missing? Are the bias diodes and thermistors okay?
Don't throw it out Glen. If you tire of it, please let me know as I love a challenge. Right now, I'm extremely poor and can't afford anything right away.
-Chris
anatech said:
The most common cause of failure on those was the stereo
lamp driver circuit. Some would fail on their own, but many times
you would get guys who would replace the stereo indicator lamp
with something that would require far too much current for its
internal circuit.
If I had any intention of throwing it away I would have already
done so. Ive kept it because the front panel is in nice cosmetic
condition. Whats missing are mostly metal hardware items.
The bottom panel is missing but that's nothing a nice piece
of sheet metal couldn't fix. There is also a metal shield that
covers one of the PC boards that's missing. All of the electronics
are there.
Hi Glen,
It's the "died on it's own" crowd. I was thinking lamp inrush current, and so installed resistance to heat up the filament in the lamp so there wasn't so much surge current. That did seem to help, but how can you tell when these things can last 15 years or so?
-Chris
Edit:
Thank you very much for responding and your observations.
Yes, that I've seen. Almost a constant throughout the many years. TV shops and newer audio shops were the most likely to stick in any lamp they had on hand. I was always very careful to keep low current stereo lamps on hand.
It's the "died on it's own" crowd. I was thinking lamp inrush current, and so installed resistance to heat up the filament in the lamp so there wasn't so much surge current. That did seem to help, but how can you tell when these things can last 15 years or so?
-Chris
Edit:
Thank you very much for responding and your observations.
Hi Glen,
Yes, I'm pretty sure you are correct there. Providing a leakage current seems to have reduced the initial surge current to within the capabilities for these chips. I haven't had any that I modified ever fail again. I just allow 10 ~ 15 mA to flow through a resistor bypass around the chip. Enough to warm up the filament, but not near enough to light it or trick the stereo decoder circuits to remain on. It's an easier change than the extra driver transistor too.
-Chris
Yes, I'm pretty sure you are correct there. Providing a leakage current seems to have reduced the initial surge current to within the capabilities for these chips. I haven't had any that I modified ever fail again. I just allow 10 ~ 15 mA to flow through a resistor bypass around the chip. Enough to warm up the filament, but not near enough to light it or trick the stereo decoder circuits to remain on. It's an easier change than the extra driver transistor too.
-Chris
well the transistors i replaced didn't have insulators and are actually supposed to have their collectors connected through the heatsink.
i bought white thermal grease specifically for this (despite the insistence by the radio shack clerk that the arctic silver 5 was better) since i ran through the rest of what i had replacing the grease on the drivers. i did order new insulators from digikey for all replaced pieces. i can't actually tell you if i overtightened the screws or not though, i obviously have no way to tell, but i feel like i applied an appropriate amount of torque.
you're correct about not being able to check the bias current. as far as i know, the service manual for the 300dc only describes how to adjust the idle current and dc-offset, which i don't have. i don't know enough to make such adjustments without the guidance of the service manual.
and i did clean off my flux, used a dremel with a nylon brush wheel.
THE 1300DC
when i say someone "got to it" i mean someone "got to it." the only thing i've replaced myself was the protection relay. i used a replacement relay from a junked marantz receiver. the one i took off had a massive carbon blob on the side that came from the left channel. the P700 board on the left channel itself had leads that were totally scorched and had been replaced by solid copper wire soldered to the board in place of the leads. more than a few of the semis were non-original and one of the caps was bloated and ready to pop (the wrapper had split). i haven't even looked at the preamp side for any tampering yet. i'm wondering if fabricating new boards for the amplifier circuits would be an easier way to go than trying to fix the ones that are already there.
i bought white thermal grease specifically for this (despite the insistence by the radio shack clerk that the arctic silver 5 was better) since i ran through the rest of what i had replacing the grease on the drivers. i did order new insulators from digikey for all replaced pieces. i can't actually tell you if i overtightened the screws or not though, i obviously have no way to tell, but i feel like i applied an appropriate amount of torque.
you're correct about not being able to check the bias current. as far as i know, the service manual for the 300dc only describes how to adjust the idle current and dc-offset, which i don't have. i don't know enough to make such adjustments without the guidance of the service manual.
and i did clean off my flux, used a dremel with a nylon brush wheel.
THE 1300DC
when i say someone "got to it" i mean someone "got to it." the only thing i've replaced myself was the protection relay. i used a replacement relay from a junked marantz receiver. the one i took off had a massive carbon blob on the side that came from the left channel. the P700 board on the left channel itself had leads that were totally scorched and had been replaced by solid copper wire soldered to the board in place of the leads. more than a few of the semis were non-original and one of the caps was bloated and ready to pop (the wrapper had split). i haven't even looked at the preamp side for any tampering yet. i'm wondering if fabricating new boards for the amplifier circuits would be an easier way to go than trying to fix the ones that are already there.
The service manual is available here: http://www.audio-circuit.dk/images/schematics/Marantz-300DC-pwr-sm.pdf
It does include a DC offset adjustment procedure, which should be doable with a modern DMM rather than the oscilloscope that the manual calls for. They are probably telling you to use a scope because meters were analog, and thus low impedance, back when this manual was written.
I don't see any options for bias adjustment, though. I think you're right about that.
Cheers,
Paul
It does include a DC offset adjustment procedure, which should be doable with a modern DMM rather than the oscilloscope that the manual calls for. They are probably telling you to use a scope because meters were analog, and thus low impedance, back when this manual was written.
I don't see any options for bias adjustment, though. I think you're right about that.
Cheers,
Paul
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