IC's are integrated circuits... the four 8 legged black parts.
Reg is regulator. The 79L15 and 78L15.
Reg is regulator. The 79L15 and 78L15.
Not sure where you are up to but this should be easily fixable.
You need the solder braid to work on this neatly and to allow you to isolate parts. I posted a link to it earlier.
Remember there is no shock hazard working on this, the only risk is a accidently shorting something out that might damage a component. So don't be scared of it...
Here's what we do. Go through these a step at a time and note the results.
1. Confirm again that the plus and minus 24volts are correct. That's points A and B. These two voltages feed the two regulators.
2. Confirm by measurement that the -24v is on the "middle" leg of the 79L15. Now look at the other two legs on that regulator. One goes to ground and the other is the output of -15 volts.
3. Confirm by measurement the voltage on this "output" leg of the 79L15. This feed goes to all the four IC's (to pin 4 on each).
I suspect now the fault will just be the regulator.
What we should do to test, is to "lift" or isolate the output pin (so it's in free space) and see if the voltage is then present on that pin. Anything other than -15 and it's duff. Unfortunately that's still not 100% foolproof as the output may appear yet the reg is unable to deliver current... unlikey scenario put just about possible.
Make sure that snipped diode is replaced/or resoldered.
If it turned out that an IC were faulty then it means pin 4 on all four IC's have to be isolated... then the -15v voltage must appear at the reg. Each IC is then recionnected in turn to find the culprit.
Maplin probably don't do the IC's fitted... but post the type number anyway. They all look to be dual opamps so there is no problem sourcing replacements and probably fitting much better.
I'll look in first thing in the morning.
Hope it makes sense... it quite simple. The output of the reg is missing. Probably just a duff reg. If the worst comes to the worse it's a reg and the IC's to fix it.
But it's nice to find the fault properly 🙂
Good luck
You need the solder braid to work on this neatly and to allow you to isolate parts. I posted a link to it earlier.
Remember there is no shock hazard working on this, the only risk is a accidently shorting something out that might damage a component. So don't be scared of it...
Here's what we do. Go through these a step at a time and note the results.
1. Confirm again that the plus and minus 24volts are correct. That's points A and B. These two voltages feed the two regulators.
2. Confirm by measurement that the -24v is on the "middle" leg of the 79L15. Now look at the other two legs on that regulator. One goes to ground and the other is the output of -15 volts.
3. Confirm by measurement the voltage on this "output" leg of the 79L15. This feed goes to all the four IC's (to pin 4 on each).
I suspect now the fault will just be the regulator.
What we should do to test, is to "lift" or isolate the output pin (so it's in free space) and see if the voltage is then present on that pin. Anything other than -15 and it's duff. Unfortunately that's still not 100% foolproof as the output may appear yet the reg is unable to deliver current... unlikey scenario put just about possible.
Make sure that snipped diode is replaced/or resoldered.
If it turned out that an IC were faulty then it means pin 4 on all four IC's have to be isolated... then the -15v voltage must appear at the reg. Each IC is then recionnected in turn to find the culprit.
Maplin probably don't do the IC's fitted... but post the type number anyway. They all look to be dual opamps so there is no problem sourcing replacements and probably fitting much better.
I'll look in first thing in the morning.
Hope it makes sense... it quite simple. The output of the reg is missing. Probably just a duff reg. If the worst comes to the worse it's a reg and the IC's to fix it.
But it's nice to find the fault properly 🙂
Good luck
Aha! Light goes on in my head!
Thanks! It was 22 years ago that I did any kind of electronic stuff. I was 15! Lol! Was more interested in the beer and chasing rabbits at Hull university! Lol!
Thanks! It was 22 years ago that I did any kind of electronic stuff. I was 15! Lol! Was more interested in the beer and chasing rabbits at Hull university! Lol!
Last post... just ask anything you are not sure over.
If Maplin haven't got a 79L15 then you can use a 79L12 and a 78L12... it shouldn't make any real difference other than slightly reduce maximum output voltage (which you won't get near anyway) and it would get it up and running.
And post those IC type...
I'll look in first thing tomorrow all being well 🙂
If Maplin haven't got a 79L15 then you can use a 79L12 and a 78L12... it shouldn't make any real difference other than slightly reduce maximum output voltage (which you won't get near anyway) and it would get it up and running.
And post those IC type...
I'll look in first thing tomorrow all being well 🙂
Right. I'll call it a night for now. Need to think.
I doubt I'll be able to solder the ic's if they are the culprit. I'll ask at Maplins tomorrow.
Got the bit between my teeth now though. Want to listen to vinyl again. Not this crisp digital stiff.
Thanks Mooly.
Your a top source of info!
And my mrs loves your avatar! Lol!
Will be a couple of days likely for an update as there is an Ill rellie in hospital!
I doubt I'll be able to solder the ic's if they are the culprit. I'll ask at Maplins tomorrow.
Got the bit between my teeth now though. Want to listen to vinyl again. Not this crisp digital stiff.
Thanks Mooly.
Your a top source of info!
And my mrs loves your avatar! Lol!
Will be a couple of days likely for an update as there is an Ill rellie in hospital!
I still think just a 79L15 will fix this... a good chance.
The two diodes, the white and the "blue" one. These appear to be fitted across the two voltage rails and as such in normal operation don't do anything. It appears they may be some form of "safeguard" to ensure the regulators "start" correctly or perhaps to minimise the possibility anything odd happening at switch off etc. 99% of circuits using these type of regs don't even bother to fit them. The "blue" one if it is marked BAT???? is a special type (very high switching speed) but as mentioned, if you just confirm there is 15 volts across this then the diode is fine.
As to unsoldring IC's or any other parts using braid. It's easy but it might be advised for you to practice on something first. Anything... an old remote etc. Practice makes perfect... and it should take around 10 to 15 seconds to remove each IC so neatly that you couldn't tell one had been fitted.
The secret is to use a "hot" iron with a fairly large tip. Make sure the tip is clean and bright and lightly tinned with a coating of fresh solder (not a blob).
One joint at a time... two methods,
1) You lay the braid over the joint and then firmly press the iron onto the top of the braid. The heat transfers instantly to the joint and should pull all the solder away cleanly.
2) Using a couple of inches of braid pull it tight "around" the iron tip. Braid in left hand, iron in right. then just touch the tip (braid) over each joint.
This shows you what I use although this thread was for working on far smaller stuff 🙂
http://www.diyaudio.com/forums/parts/127924-working-smd-how-do-without-specialised-tools.html
You won't know if any of the IC's are faulty until you replace the reg.
I'm still puzzled how it could all of failed just by using a 16v DC supply... never know I guess.
The two diodes, the white and the "blue" one. These appear to be fitted across the two voltage rails and as such in normal operation don't do anything. It appears they may be some form of "safeguard" to ensure the regulators "start" correctly or perhaps to minimise the possibility anything odd happening at switch off etc. 99% of circuits using these type of regs don't even bother to fit them. The "blue" one if it is marked BAT???? is a special type (very high switching speed) but as mentioned, if you just confirm there is 15 volts across this then the diode is fine.
As to unsoldring IC's or any other parts using braid. It's easy but it might be advised for you to practice on something first. Anything... an old remote etc. Practice makes perfect... and it should take around 10 to 15 seconds to remove each IC so neatly that you couldn't tell one had been fitted.
The secret is to use a "hot" iron with a fairly large tip. Make sure the tip is clean and bright and lightly tinned with a coating of fresh solder (not a blob).
One joint at a time... two methods,
1) You lay the braid over the joint and then firmly press the iron onto the top of the braid. The heat transfers instantly to the joint and should pull all the solder away cleanly.
2) Using a couple of inches of braid pull it tight "around" the iron tip. Braid in left hand, iron in right. then just touch the tip (braid) over each joint.
This shows you what I use although this thread was for working on far smaller stuff 🙂
http://www.diyaudio.com/forums/parts/127924-working-smd-how-do-without-specialised-tools.html
You won't know if any of the IC's are faulty until you replace the reg.
I'm still puzzled how it could all of failed just by using a 16v DC supply... never know I guess.
Thanks for all your help Karl,
I'll get the 79L15 and a 78L15 today (or 79L12) as well as ther solder braid.
I think I have an old remote lying around somewhere.
I did noptice when I unsoldered the Diodes that the board seemed to like to get rid of it's solder quickly, leaving a dry little circle. What would be best to sort this issue out?
I've sorted it this time by bridging the gap between the two diodes with solder as one leg was just loose after soldering. I'm thinking my solder is just so old and dirty that it's time to get some new modern stuff. My iron seems fine and the tip is fairly large, about electrical screwdriver width.
I've had a read of the SMD thread, all good stuff. I'll try and apply some of tose techniques. Although my dining room table isn't exactly a heated workstation! LOL!.
Cheers, speaks soon.
I'll get the 79L15 and a 78L15 today (or 79L12) as well as ther solder braid.
I think I have an old remote lying around somewhere.
I did noptice when I unsoldered the Diodes that the board seemed to like to get rid of it's solder quickly, leaving a dry little circle. What would be best to sort this issue out?
I've sorted it this time by bridging the gap between the two diodes with solder as one leg was just loose after soldering. I'm thinking my solder is just so old and dirty that it's time to get some new modern stuff. My iron seems fine and the tip is fairly large, about electrical screwdriver width.
I've had a read of the SMD thread, all good stuff. I'll try and apply some of tose techniques. Although my dining room table isn't exactly a heated workstation! LOL!.
Cheers, speaks soon.
Sounds like you need some new solder. Not sure what Maplin have without looking. The print on these boards is quite fine and delicate so the secret is to only apply heat (quickly) and pressure. Never move or scrub the iron of the pads as that will lift and break them.
Soldered joints should be clean and bright... I'll have a quick look what Maplin do.
Soldered joints should be clean and bright... I'll have a quick look what Maplin do.
All lead free now of course... which has a higher melting point then the "old" stuff.
solder : Maplin Electronics
Can't see a 79L15 only 79L12
voltage regulator : Maplin Electronics
You know you can check store stock from this site.
You could also use the 7915 in place of the 79L15 regs (the larger 1 amp type) if needed.
solder : Maplin Electronics
Can't see a 79L15 only 79L12
voltage regulator : Maplin Electronics
You know you can check store stock from this site.
You could also use the 7915 in place of the 79L15 regs (the larger 1 amp type) if needed.
Gotta go 🙂
You might get solder at some DIY stores/50P shops etc in small tubes. You want the thin electronics stuff, not plumbers solder etc. Mustn't be an acid flux.
Soldering Guide
If you can practice on an old remote or anything that's great.
You might get solder at some DIY stores/50P shops etc in small tubes. You want the thin electronics stuff, not plumbers solder etc. Mustn't be an acid flux.
Soldering Guide
If you can practice on an old remote or anything that's great.
Right, as requested the numbers off the IC's
4580D is the one that Mooly identified, the other reads (in full)
MAL TL061CN 90A727
Still can't read what the blue diode is except that it has BAT on it.
Cheers all.
I'm off to Maplins!!
4580D is the one that Mooly identified, the other reads (in full)
MAL TL061CN 90A727
Still can't read what the blue diode is except that it has BAT on it.
Cheers all.
I'm off to Maplins!!
If you are a newbie unsoldering. May I suggest the following.
Take a sharp Craft Knife and slice the legs of each IC as close to the body of the IC as possible. Physically remove the black plastic body of the IC.
THEN, unsolder each leg in turn. In this way you don't have to worry about one or two being tricky to remove. Each one can just be heated and pulled.
This is a must with bigger ICs as two or more pins that are through soldered - not a problem in this case - will make the IC very awkward to remove.
Of course it will destroy the IC but they are only pennies.
If you do a search for Pro-Phono on this site you will find a thread that is dedicated to upgrading this unit.
Many guys have replaced the ICs with NE5532s or even more exotic devices, but have had to add extra decoupling (capacitors across the ICs).
Personally I think the ICs will be OK. Most of them can easilly handle +/- 18V which is well below what you have subjected the board to.
Take a sharp Craft Knife and slice the legs of each IC as close to the body of the IC as possible. Physically remove the black plastic body of the IC.
THEN, unsolder each leg in turn. In this way you don't have to worry about one or two being tricky to remove. Each one can just be heated and pulled.
This is a must with bigger ICs as two or more pins that are through soldered - not a problem in this case - will make the IC very awkward to remove.
Of course it will destroy the IC but they are only pennies.
If you do a search for Pro-Phono on this site you will find a thread that is dedicated to upgrading this unit.
Many guys have replaced the ICs with NE5532s or even more exotic devices, but have had to add extra decoupling (capacitors across the ICs).
Personally I think the ICs will be OK. Most of them can easilly handle +/- 18V which is well below what you have subjected the board to.
Cutting IC's close to the body is certainly one way, as Andy says particularly when dealing with double sided boards and plated through vias.
The Op-Amps,
The 4580 dual Op-Amp is one of the myriad devices available to manufacturers and very suitable for experimenting with as regards replacing. I wouldn't like to say how good subjectively the device is... it's one that would never get recommended to be used on DIYaudio I suspect. It's just a cooking grade jelly bean device.
http://www.datasheetcatalog.org/datasheet2/3/07d8effaffpq3uiop24apeo98dyy.pdf
Almost any of the popular types would be a direct replacement... that's the beauty of opamps (within reason).
The NE5532 is available at Maplins... you either love it or hate it I guess but it's been the industry standard for the last couple of decades in studio gear and consoles.
The LM4562 is it's successor.
Personally I like the OPA2604 which is a FET device, and that would work here too.
The TL072 is available at Maplin, another FET device that would give you an idea of subjective differences between the the 4580 and "others".
When it's all working if you want to try swapping, then fitting a socket for each 4580 is recommended. Then you can try several different devices for yourself.
The TL061 is a low power FET "single" Op-Amp. It almost certainly isn't in the audio path... if it is it shouldn't be 🙂... but it's more than likely used as a DC servo for which it is ideal.
But first you have to get it all working.
The Op-Amps,
The 4580 dual Op-Amp is one of the myriad devices available to manufacturers and very suitable for experimenting with as regards replacing. I wouldn't like to say how good subjectively the device is... it's one that would never get recommended to be used on DIYaudio I suspect. It's just a cooking grade jelly bean device.
http://www.datasheetcatalog.org/datasheet2/3/07d8effaffpq3uiop24apeo98dyy.pdf
Almost any of the popular types would be a direct replacement... that's the beauty of opamps (within reason).
The NE5532 is available at Maplins... you either love it or hate it I guess but it's been the industry standard for the last couple of decades in studio gear and consoles.
The LM4562 is it's successor.
Personally I like the OPA2604 which is a FET device, and that would work here too.
The TL072 is available at Maplin, another FET device that would give you an idea of subjective differences between the the 4580 and "others".
When it's all working if you want to try swapping, then fitting a socket for each 4580 is recommended. Then you can try several different devices for yourself.
The TL061 is a low power FET "single" Op-Amp. It almost certainly isn't in the audio path... if it is it shouldn't be 🙂... but it's more than likely used as a DC servo for which it is ideal.
But first you have to get it all working.
Well, after a successful visit to Maplins last week today was a complete cop out.
Apparently the technical guy doesn't work Sunday's, and the bloke today couldn't find what I needed whatsoever. Then when I finally found a 1amp 7915 it was web only.
So, where's a good place online to buy the components I need?
I'm not doing another 100 mile round trip to Maplins again!
Apparently the technical guy doesn't work Sunday's, and the bloke today couldn't find what I needed whatsoever. Then when I finally found a 1amp 7915 it was web only.
So, where's a good place online to buy the components I need?
I'm not doing another 100 mile round trip to Maplins again!
That's a pity... mind you at Maplin prices lol
CPC is pretty good and very quick but there will be a delivery charge for small orders.
CPC | CPC - Over 100, 000 products from one of the worlds leading distributors of electronic and related products.
79L15 is out of stock... but order anyway, they send them on for no extra charge.
The 79L12 is fine to get it working.
Order codes,
79L12 is SC08492
78L12 is SC08371
79l15 is SC08498
78L15 is SC08387
1N4007 is SC07337 (minimum order of 10)
Sockets are SC08116 worth getting four of these if you want to have a play with better Op-Amps.
Op-Amps. I would order at least a "new set" then you have all you need if there are problems. So that's two of each depending what you want.
So that's at least two TL061's and two NE5532's. The others are if you fancy trying others to listen too. The sockets make it easy to swap and compare.
TL061 is SC07337
NE5532 is SC07985
TL072 is SC07921
OPA2604 is SC07958
Solder Braid is SD01165
Solder, depends how much you want to pay, but you can get through it quickly,
Your Search Results | CPC
As the diode was zapped I would also perhaps replace the two "large" black capacitors. If you tell me the markings on them I can find replacements.
Make sure you check all the part numbers... and what is expected appears 🙂
CPC is pretty good and very quick but there will be a delivery charge for small orders.
CPC | CPC - Over 100, 000 products from one of the worlds leading distributors of electronic and related products.
79L15 is out of stock... but order anyway, they send them on for no extra charge.
The 79L12 is fine to get it working.
Order codes,
79L12 is SC08492
78L12 is SC08371
79l15 is SC08498
78L15 is SC08387
1N4007 is SC07337 (minimum order of 10)
Sockets are SC08116 worth getting four of these if you want to have a play with better Op-Amps.
Op-Amps. I would order at least a "new set" then you have all you need if there are problems. So that's two of each depending what you want.
So that's at least two TL061's and two NE5532's. The others are if you fancy trying others to listen too. The sockets make it easy to swap and compare.
TL061 is SC07337
NE5532 is SC07985
TL072 is SC07921
OPA2604 is SC07958
Solder Braid is SD01165
Solder, depends how much you want to pay, but you can get through it quickly,
Your Search Results | CPC
As the diode was zapped I would also perhaps replace the two "large" black capacitors. If you tell me the markings on them I can find replacements.
Make sure you check all the part numbers... and what is expected appears 🙂
If you are simply after the regulators, I would try E-Bay.
No one has bothered to fake 79 or 78 series regulators as it just aint worth it.
No one has bothered to fake 79 or 78 series regulators as it just aint worth it.
Last edited:
Hi all,
Ordered the voltage regulators off Ebay today so will hopefully arrive for the weekend. Then watch this space!
I got 3x 78L15's and 5x 79L15's as they were the numbers they came in. Both UK stockists so that's good!
I'll let you know how it all goes!
Ordered the voltage regulators off Ebay today so will hopefully arrive for the weekend. Then watch this space!
I got 3x 78L15's and 5x 79L15's as they were the numbers they came in. Both UK stockists so that's good!
I'll let you know how it all goes!
- Status
- Not open for further replies.