So I go to turn the old girl on this afternoon, and I get lights, and meters, but no familiar "click" of the relay. So I know I'm screwed, but I didn't know how screwed. I sent an email to the best stereo guy in Austin who tells me it's probably 10 weeks, and $700-800. That's not to fix the problem and I know that. He does quality work and he will not bother opening one up without fully recapping, cleaning and converting lights to LEDs. But $800? Really? Is that what it costs these days?
KR 7600 Repairs
- Thread starter JRW
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If this is what I can expect to pay an expert, then I may as well buy a temporary replacement on CL and start buying the basic tools and reteach myself how to solder. It's been awhile, and my eyes aren't as good, but I can buy another old 7600 that hasn't been recapped for $450.00.
JR, if you want to fix it yourself, we can help. I looked at the restore sticky and didn't see a KR7600 but i did find @hopjohn authored post that may be helpful to get started.
I've fixed a few lower powered receivers and do own a KR9400.
hifi engine has the service manual. download it (free signup if you haven't) and study it. Sometimes I print out the schematic in 11x17 for my poor eyes.
I've fixed a few lower powered receivers and do own a KR9400.
hifi engine has the service manual. download it (free signup if you haven't) and study it. Sometimes I print out the schematic in 11x17 for my poor eyes.
The guy I contacted is THE guy in Austin and he's been at it 30 years. Austin thinks of itself as the new San Diego so everything there is expensive. He will not fix a receiver. If he takes it in, it gets fully restored, otherwise, someone else can do it. I respect him for that but I can't spend that much $ on a receiver I bought off CL for $185.00.
I will have to start by getting a space set up. I'll check out the DIY pages. I think I may buy a temporary replacement receiver. This monster is way too much for the ADS 520s. Is this how the sickness begins?
I will have to start by getting a space set up. I'll check out the DIY pages. I think I may buy a temporary replacement receiver. This monster is way too much for the ADS 520s. Is this how the sickness begins?
Also, I took Electronics in 7th grade. I put together a Heathkit strobe light kit and got an A. I have soldered 5 times in the ensuing 45 years. Is there an Electronic Repair For Dummies or such that will help me reacquaint with terminology so I can phrase questions in reasonably accurate terms? I really am in the baby steps phase.
For THE guy and a FULL recap, the price is within reason, though a tad towards the high side.
A repair can cost $100-$300 fairly easily depending on how much damage there is.
It’s pretty easy to spend 3-4 hours working on a simple repair. A messed up unit can take days.
Insisting on full rebuild only is stiff, but it does cut down returns.
A repair can cost $100-$300 fairly easily depending on how much damage there is.
It’s pretty easy to spend 3-4 hours working on a simple repair. A messed up unit can take days.
Insisting on full rebuild only is stiff, but it does cut down returns.
If you end up getting it into good operating condition, the 7600, rated at 70 watts, is just fine for your ADS speakers. Headroom is a good thing...reduces the potential for distortion at higher volumes.
I really like the faceplate and display of that receiver. Just wish they had used a normal cabinet...not a fan of the faux heatsink fins.
I've started my basic education on electronics and it's going to be ok. I can do this. In the meantime. I have found two potential replacement receivers while the 760 is in dry dock. Sansui 3300 for $200, or a KR 3010 for $150. I'm on the Kenwood board, but honest analysis appreciated.
i'd put the receiver on a DBT and start measuring voltages to determine where is the problem.
Gort's photobucket image shows voltages. Since both AKdatabase and hifi engine seem to have the same source, you will need to figure out if the voltages are in spec.
Looking at PS A, pins 4 (ground), 7, 8 are PS voltages IN.
pin 1 might be + and pin 6 might be - voltage OUT. pin 4 is still ground. Hopefully gort will post his scan or confirm.
I'd verify the PS voltages are close before testing transistors. If you use a DBT, you will limit the current and hopefully prevent more damage. I'd use a 60-75w bulb. Also know that a DBT will reduce the voltages compared to the schematic but will be consistent. Post your results.
If the voltage IN looks suspect, you need to look at PS C.
To answer your question, yes, 5 transistors on PS board A.
Gort's photobucket image shows voltages. Since both AKdatabase and hifi engine seem to have the same source, you will need to figure out if the voltages are in spec.
Looking at PS A, pins 4 (ground), 7, 8 are PS voltages IN.
pin 1 might be + and pin 6 might be - voltage OUT. pin 4 is still ground. Hopefully gort will post his scan or confirm.
I'd verify the PS voltages are close before testing transistors. If you use a DBT, you will limit the current and hopefully prevent more damage. I'd use a 60-75w bulb. Also know that a DBT will reduce the voltages compared to the schematic but will be consistent. Post your results.
If the voltage IN looks suspect, you need to look at PS C.
To answer your question, yes, 5 transistors on PS board A.
Remove the top cover. The power supply A board is in the front right hand corner.
The suspects are Qk1 and Qk5. These are the voltage regulators. Qk1 failure is very common. (The transistor with the heat sink)
Meter set to read DC voltage - black lead to chassis for ground - red lead to pin # under test.
Power up unit
Pin # 1 +52VDC
Pin #6 -52VDC
Pin #2 +23VDC
Pin #5 -23VDC
The voltage I'd expect to see screwed up is the +23vdc at pin #2, but if any of these four are way off the protect (relay) circuit won't work. There are other simple things to check - such as fuses - but this is a good place to start. I expect both fuses are fine since you get lights and meters.
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I found the components needed packaged up for sale. I then set out to find a spot in my house to set up a table, I would also have to obtain. I no longer have a functioning soldering iron, and I need a test meter. Then I found a guy who would fix what's wrong for up to $175.00 (includes parts) or if it's bad, he'll call me and give me the bad news before he goes any farther, at no charge. He has a very good reputation.
This is my only decent receiver, at this point. I am intrigued by the prospect of being able to repair and recap my own stuff, but this is not the time, and the old 7600 is not the one. I need someone who is cpable in this regard, to help me learn as I go. This forum is incredible and I look forward to the process. It just isn't time for me t do it. I need to find a garage sale diamond in the rough, and set up a work station where I can walk away from it when I need to. Thank all of you so much for your advice.
This is my only decent receiver, at this point. I am intrigued by the prospect of being able to repair and recap my own stuff, but this is not the time, and the old 7600 is not the one. I need someone who is cpable in this regard, to help me learn as I go. This forum is incredible and I look forward to the process. It just isn't time for me t do it. I need to find a garage sale diamond in the rough, and set up a work station where I can walk away from it when I need to. Thank all of you so much for your advice.
I figure a full resurrection would take up to two days on the bench, so I understand the cost. I just can't pay that at this time. I could probably find some really nice gear out there that's been recapped already at that price. I'll get as much done as I can afford, and start putting money back for a good meter, iron, and a folding table, then it's off to the garage sales.