I have a shop but it's not the type with a storefront. I mainly work for car audio shops/dealers.
I generally try to answer questions when an amp is being bench-tested or when I'm working on a computer (which is mostly waiting for the computer/software) and I can't do anything else.
I don't know if I love what I do but I try to make up for those who refuse to share (useful) knowledge.
I generally try to answer questions when an amp is being bench-tested or when I'm working on a computer (which is mostly waiting for the computer/software) and I can't do anything else.
I don't know if I love what I do but I try to make up for those who refuse to share (useful) knowledge.
I use to custom car audio installations when i was in college. When i graduated college i took a job doing instrumentation electronics and calibrations for a pharmaceutical company. What was neat about working at the car audio store is all the free amps i could get that were damaged or blown. I would take them to electronics class and start repairing them. that was in 1995. Well you are definitely a wealth of knowlege.
Same, but i've been doing it so long i've spawned off into other areas of repair though so now and then I lose touch with some of the new stuff in CA.
Likewise as well on the first part. I think 'fixers' will always feel compelled to fix. Even long after we no longer 'feel' any satisfaction from it. It's just in our nature.
On the second part, I think something should be said, and i'm in no way trying to disrespect or speak on behalf of Perry, it's a personal observation and opinion of my own that follows. It'll probably get buried after a whopping 3 people see it, but i'm going to say it any way. So here is my mini soapbox rant.
Some of you are so ******* lazy and ungrateful I wouldn't give you the time of day, let alone help you repair something.
I'm not naming names, pointing fingers, or anything of the sort. But look through page after page of this forum. It's not a refusal to share useful knowledge by any means, rather a refusal to become an amplifier repair welfare office that keeps me quiet most of the time.
To insinuate that some people just refuse to share without considering the reasons is a little harsh to throw out there into the wind. I for example share plenty, I'm just more selective when I chose the battles. I have a LOT of hobbies so I pitch in on other forums geared toward other things. I come here mainly to read, learn, and throw a comment out on occasion. I can't give all my time to everything and I certainly won't give it to people who can barely spoon feed themselves.
Perry has already archived his useful knowledge, that's not what's going on here though. Baring any new developments he has erected websites that do this (FREE) and a DVD tutorial geared specifically at helping people learn and understand this; And it's CHEAP. The links, aside from the paid tutorial are all over his signature (forum advert rules?) But if you follow the yellow brick road, you can get a DVD full of schematics, high resolution photographs and repair tips by manufacturer.
Yet not a day goes by that I don't see a thread from a 'tech' that 'just got another one of these in the shop' and asks 'where do I start?'
Oh.. I don't know.. Turn your meter on and begin electronics 101?
IMHO, Perry has already shared his useful information and people are just too lazy to bother looking for it. I can't tell you how many times I've seen threads where people can't be bothered to open a new browser tab and look at a data sheet. Some times they won't even run a thread search on the forum first! Why help them? A portion of my work earnings is already ripped from my pockets to pay welfare and SSI.
In my eyes there is also a large difference between sharing knowledge and holding your hand through a repair you're charging someone else to do. If you're making money off this stuff, He should get something for that. Knowledge is free, but if you want someone else to practically do the repair for you while you wander about the PCB with your meter like a zombie then you shouldn't be collecting a check for that; he should. This also goes for the weekend shade tree techs that buy, repair, and flip amps as a side income. you're still consistently making money off another persons back.
When I got started, I wasn't perfect. I had basic electronics and basic tools. None of that will prepare you for field experience however as any real tech knows. But I always exhausted ALL of MY OWN EFFORTS before consulting a peer, which included but are not limited to:
Calling distributors for free catalogues and sourcing my own parts.
Calling around for schematics and manufacturer specific parts.
Sourcing and making custom tools and learning to fabricate.
Data sheet collection, on paper! in binders! Labeled and catalogued.
Brute force, shotguning, head banging and the brink of violence before giving up.
Some of these people around here don't even want to GOOGLE a part number! I didn't even have the internet when I started! I use to sit on the toilet and read data sheets instead of magazines and i'm suppose to help people who can't use a search form? Then they say they have a shop!
There was a time when people TRIED to do things themselves or sought the information to do so. Now people just skip all that and go straight to asking someone else to do it for them. Is this becoming the 'nanny state of car audio repair' ?IMHO Perry is aiming for sainthood with some of the users here. I couldn't do it and I have patience too. If I seen another peer in my occupation reaching out to me and realized they did everything they could, I would gladly help. But I just don't see that too often, and when I do Perry is already on top of it.
Sharing useful information when others refuse to is just not how I see it, all due respect. Some of us (me) come to a moral standstill when they see these patterns of behaviour. I would pick a man up who fell from trying to get up before I would pick a man up who just wants to lay there on the ground.
'Post the voltages on pin 1-8 of u-xxx'
Is not sharing useful information. It's remotely controlling someones hands from miles away. In my opinion this contributes to the world getting DUMBER, not wiser. And leaves you with 'experts' that know nothing long after we're dead and gone. Which I gathered from your recent website updates and notes is the sort of thing your hoping to provide against, and then you seemingly contribute to some form of it here?
I respect you, I thank you, I've even supported you; But I do not understand this at all. And before anyone goes and get's offended, know that the only people who should be offended by this are the offenders. So when you get angry, reflect.
Next time I see a post of a weekend warrior makin a buck or a 'shop owner' asking where to start, i'm posting the link to some 'useful information' - The owners manual that tells them how to hook it up. Because clearly, this is where the worst of the worst need to start.
And even if I did just go -10,000 brownie points into the hole around here, I still wish you all a fantastic Sunday
wow...i don't know how to even respond to that....I guess i would fall in the weekend warrior group. I do buy amps broken when i can and fix them to the best of my ability and knowledge and sell them. I do offer a 30 day warranty on them when i do sell them.
I feel i have a good amount of knowledge with rockford fosgate amps and these are the ones i tend to keep repairing and restoring. But, there are times when i am just stumped with a repair and look like a zombie. I don't want anyone to fix an amp for me because that would defeat the purpose of me learning. Besides, if i can't fix it then becomes a part amp for me or until i have crazy idea or thought and go back and try something different with that particular amp. I am glad you got this off your chest and i am not offended by any means to each there own. i do hope that one day when i need some help i can also look to you for some help.
matt,
I feel i have a good amount of knowledge with rockford fosgate amps and these are the ones i tend to keep repairing and restoring. But, there are times when i am just stumped with a repair and look like a zombie. I don't want anyone to fix an amp for me because that would defeat the purpose of me learning. Besides, if i can't fix it then becomes a part amp for me or until i have crazy idea or thought and go back and try something different with that particular amp. I am glad you got this off your chest and i am not offended by any means to each there own. i do hope that one day when i need some help i can also look to you for some help.
matt,
I'm not above helping you, as long as I a) have the time and b) you try and help yourself first. The soap box rant wasn't really geared toward you, unless you feel it was. Did you know the trick he showed you with the POT is part of his DVD as well?
Next amplifier you flip, you should make a tiny investment into 'continued education'
Next amplifier you flip, you should make a tiny investment into 'continued education'
That's the thing about the DVD, it's not just videos. It has flash examples, repair notes by manufacturer, tricks of the trade, a decent schematic database and much more. It navigates like his website, only has more pertinent information geared towards what you want to do.
I've been doing this a long time, but Perry helped me 3-4 times when I got stuck with absolute basket cases. One of which he successfully aided me in repairing, two I managed to catch the issue between emails (but i'm thankful he answered) and one is just plain going back to Crossfire and they can deal with the Dlogix BS. He has also taken his time to email me things on weekends when I could have waited till monday to contact someone else during business hours.
As a thank you, I got a copy of it. It's like saying 'Hey, have lunch on me today.. I appreciate it!' While I didn't need the basic areas of the tutorial, the extras I found surprisingly useful and am happy to have as a reference in one place. It will pay itself off, even for me. I consider that part of continued education and it helps stay on top of little manufacturer nuances as well.
Keep pluggin away at those Rockfords! I did 2 this weekend. A 200s and a 200DSM (which was a complete ballbreaker..)
I've been doing this a long time, but Perry helped me 3-4 times when I got stuck with absolute basket cases. One of which he successfully aided me in repairing, two I managed to catch the issue between emails (but i'm thankful he answered) and one is just plain going back to Crossfire and they can deal with the Dlogix BS. He has also taken his time to email me things on weekends when I could have waited till monday to contact someone else during business hours.
As a thank you, I got a copy of it. It's like saying 'Hey, have lunch on me today.. I appreciate it!' While I didn't need the basic areas of the tutorial, the extras I found surprisingly useful and am happy to have as a reference in one place. It will pay itself off, even for me. I consider that part of continued education and it helps stay on top of little manufacturer nuances as well.
Keep pluggin away at those Rockfords! I did 2 this weekend. A 200s and a 200DSM (which was a complete ballbreaker..)
Perry,
I used the scope with your tutorial and all my waveforms are in the correct spots except at the rail switching Fets and the audio output Fets. I pulled both MIC4420 drivers to check them more thoroughly. I also powered the amp and verified that there was a square wave on the 4420 input. both of the 2211 opto coupler outputs are at ~8. the Fets had 110v on them and i was expecting ~45 to 50. There was also no switching square wave on there outputs. My question is how does the Fet get the full rail voltage on it?
I used the scope with your tutorial and all my waveforms are in the correct spots except at the rail switching Fets and the audio output Fets. I pulled both MIC4420 drivers to check them more thoroughly. I also powered the amp and verified that there was a square wave on the 4420 input. both of the 2211 opto coupler outputs are at ~8. the Fets had 110v on them and i was expecting ~45 to 50. There was also no switching square wave on there outputs. My question is how does the Fet get the full rail voltage on it?
The output transistors don't have any pulldown resistors. When the drivers are out of the circuit and the amp is powered up, you risk blowing the outputs.
If you had a square wave signal on the input pins of both 4420s, the drive circuit is likely OK.
Which pins of the opto-coupler were at 8v.
Were all components in the circuit when you measured the voltage that you posted above?
If you had a square wave signal on the input pins of both 4420s, the drive circuit is likely OK.
Which pins of the opto-coupler were at 8v.
Were all components in the circuit when you measured the voltage that you posted above?
Yes..It was on Pin 7. They maybe operating properly and i am over analyzing the scenario. Correct if I'm wrong..the IC driver 4420 is fed by a square wave signal and cycles between +10V and -10V on the output. The -10V turns on the irf6215's and +10V turns on the irf3415's. So should you see a square wave on the output pin of the IC driver?
#37:
You will see this on the FETs for the rail switching FETs but you may not see this clearly on the FETs that drive the output to the speaker terminals because the FETs driving the speaker terminals are floating.
The rail voltage on the FETs is constantly switching unless there is a problem or the amp is in protect/mute delay.
If you have the tutorial, read the BD1500 page in the Rockford folder.
You will see this on the FETs for the rail switching FETs but you may not see this clearly on the FETs that drive the output to the speaker terminals because the FETs driving the speaker terminals are floating.
The rail voltage on the FETs is constantly switching unless there is a problem or the amp is in protect/mute delay.
If you have the tutorial, read the BD1500 page in the Rockford folder.
Perry
Can the amp be in protect mode even when the Protect LED goes off after 1.5 secs.
I am waiting for parts from Newark. I ordered the ic driver 4420, op-amps, and opto-couplers. I was measuring 110v on the fets before i removed the FETS and IC Drivers. I also had a square wave on the inputs of the ic driver. The outputs on both 4420's were both positive ~9v and were not oscillating.
If both drivers are output a non oscillating +9v will that cause the 110v on the FETs?
Can the amp be in protect mode even when the Protect LED goes off after 1.5 secs.
I am waiting for parts from Newark. I ordered the ic driver 4420, op-amps, and opto-couplers. I was measuring 110v on the fets before i removed the FETS and IC Drivers. I also had a square wave on the inputs of the ic driver. The outputs on both 4420's were both positive ~9v and were not oscillating.
If both drivers are output a non oscillating +9v will that cause the 110v on the FETs?
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