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GK 1001RB II amp repair - help!

#41
74hc said:
Looks like you damage the trace on the PCB, and probably the thru-hole plating as well. You could try to reflow the solder, but always use the minimal amount of heat with a temperature controlled soldering station.

Check Youtube for desoldering. I prefer using the solder wick method.

Don't use the the cheap junk with just a solder handle and an electrical cord.

Full Compass sells the preamp board for under $100.
Click to expand...

Yup, likely the PCB was damaged from improper removal of the jack. Unfortunately, I see this pretty regularly and it's costly to repair properly when a replacement PCB is no longer available. This would have been a $75 flat rate repair in my shop but now IF the pcb is available, that's probably your best bet.

For double sided boards with plated holes, NEVER try to remove the part using suction or braid. Deconstruct the part (jacks like this deconstruct just like they were assembled), heat each pad up individually and remove the lead (not the whole part) from the hole. Then once all of the holes are free of leads, then a quick suction and throw the braid away. With the higher temperatures of lead-free solder, it's easy to damage a board if you don't know what you are doing (like what happened here). I haven't damaged a PCB in as long as I can remember, and that includes rework scenarios too, but I have certainly seen the effects based on what comes in from the field.
 
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#42
The JST connectors are polarized, the base of the male part came off with the female, it's clearly marked on the board the orientation. This is not uncommon. It needs to be installed correctly.
 
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#43
TubeDood said:
ordered a new preamp from Full Compass for 70$
Click to expand...
74hc said:
Full Compass sells the preamp board for under $100.
Click to expand...

Last night this thread made me check up on that - I don't think they're available any longer through Full Compass. At the very least they don't appear to be listed on their site. Not sure if it's temporary, or if they'll no longer be carrying them due to the RB series being discontinued.

Might have to get them straight from GK in the future.
 
#44
agedhorse said:
Yup, likely the PCB was damaged from improper removal of the jack. Unfortunately, I see this pretty regularly and it's costly to repair properly when a replacement PCB is no longer available. This would have been a $75 flat rate repair in my shop but now IF the pcb is available, that's probably your best bet.

For double sided boards with plated holes, NEVER try to remove the part using suction or braid. Deconstruct the part (jacks like this deconstruct just like they were assembled), heat each pad up individually and remove the lead (not the whole part) from the hole. Then once all of the holes are free of leads, then a quick suction and throw the braid away. With the higher temperatures of lead-free solder, it's easy to damage a board if you don't know what you are doing (like what happened here). I haven't damaged a PCB in as long as I can remember, and that includes rework scenarios too, but I have certainly seen the effects based on what comes in from the field.
Click to expand...

As always, Agedhorse nailed it.
Depending on the situation, I may end up with a small pile of connector pieces and a pristine PWB. I'll cut the plastic or contact material to remove each through hole lead one at a time. Clean and wick the PTH and clean. Perfect. Same with blown DIP ICs, cut the leads up next to the plastic component body and take them out one at a time. It's not pretty, but its quick and works great. I had a customer ask for the removed parts back (not sure why, but it's their right) and I dont think he was too pleased to get a bag of scraps back. But they are paying by the hour, so what's more important - pristine dead parts or a smaller repair bill.

We use SMT mezzanine connectors at work (usually Samtec) and I can remove a 25x2 in a matter of minutes by taking the plastic housing off first and ghen removing each lead. Wick & clean. Perfect.
 
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#45
AudioTaper said:
As always, Agedhorse nailed it.
Depending on the situation, I may end up with a small pile of connector pieces and a pristine PWB. I'll cut the plastic or contact material to remove each through hole lead one at a time. Clean and wick the PTH and clean. Perfect. Same with blown DIP ICs, cut the leads up next to the plastic component body and take them out one at a time. It's not pretty, but its quick and works great. I had a customer ask for the removed parts back (not sure why, but it's their right) and I dont think he was too pleased to get a bag of scraps back. But they are paying by the hour, so what's more important - pristine dead parts or a smaller repair bill.

We use SMT mezzanine connectors at work (usually Samtec) and I can remove a 25x2 in a matter of minutes by taking the plastic housing off first and ghen removing each lead. Wick & clean. Perfect.
Click to expand...
Agreed, but with smaller diameter plated holes, wick is not very effective and very much increases the chances for damage to the PCB. Suction is generally much safer.
 
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#47
agedhorse said:
The JST connectors are polarized, the base of the male part came off with the female, it's clearly marked on the board the orientation. This is not uncommon. It needs to be installed correctly.
Click to expand...
I put them back on the right way, but not sure it matters. What I'm finding is when doing continuity checks the back two pins on the input jack don't really show anything. So either I fudged the solder joints or fudged the board. Unfortunately there is only one amp tech where I live (San Jose) and apparently it takes months to get an amp repaired. Might have to bite the bullet and chalk it up to lesson learned.
 
#48
chowderhead1962 said:
I put them back on the right way, but not sure it matters. What I'm finding is when doing continuity checks the back two pins on the input jack don't really show anything. So either I fudged the solder joints or fudged the board. Unfortunately there is only one amp tech where I live (San Jose) and apparently it takes months to get an amp repaired. Might have to bite the bullet and chalk it up to lesson learned.
Click to expand...

Talk to GK. See if they can send you a new preamp that you can drop in, and just be extra careful installing it. As noted before, you used to be able to pick them up on Full Compass for like $70. Small price to pay IMO as long as nothing else gets goofed up in the process.

Of course... if you're unsure at all about the process or would rather it just be handled by a professional at this point, by all means go that route!
 
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#49
It absolutely does matter what direction those headers are installed.

There are plenty of qualified techs in your area. Give GK a call and see who they might recommend.

If you chalk it up to a lesson learned, hopefully others will learn from your experience and gain some value from it. I see the results of your attempt pretty regularly, not just from end users but also from techs who should put down the soldring iron and look for another career that they are better suited to. You are not alone, you have plenty of company, including DIY self-help YouTube videos that pretend to know what they are talking about.
 
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#50
chowderhead1962 said:
I did not test that no. Does that just involve touching the solder joint with one lead on a voltmeter and then jack itself with the other?
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chowderhead1962 said:
I did not test that no. Does that just involve touching the solder joint with one lead on a voltmeter and then jack itself with the other?
Click to expand...
If you can't answer this question, YOU HAVE NO BUSINESS WORKING ON THAT AMPLIFIER! STOP!!!!
 
#51
agedhorse said:
Suction is generally much safer.
Click to expand...

images(14).jpg
 
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#53
Kro said:
Talk to GK. See if they can send you a new preamp that you can drop in, and just be extra careful installing it. As noted before, you used to be able to pick them up on Full Compass for like $70. Small price to pay IMO as long as nothing else gets goofed up in the process.

Of course... if you're unsure at all about the process or would rather it just be handled by a professional at this point, by all means go that route!
Click to expand...
BTW, I did check Full Compass and I didn't see any 1001RB II preamps on the site. Plenty of other parts, but not those unfortunately.
 
#59
I just wanted to follow up on this post as the outcome was interesting. The tech who repaired my amp ended up having to do some wire tracing to repair what I had done (lesson learned), but he also noted that the solder job done at the effects/tuner jacks at the GK factory were terrible and that there was flux eating into the board. He ended up cleaning all of that up as well. What I noticed as an end result is that the Amp sounded WAY better after repair than it had even prior to my needing the input jack replaced. The GK factory did a number on this amp at creation, but now it sound like it was supposed to in the first place.
 
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#60
My GK1001RB had to go back to GK a few years ago, under warranty. They had the amp for a couple months, "upgraded" a few things but did not fix the problem I sent it in for...the horn amp wasn't passing signal. (They test it at 10kHz, but it wasn't passing anything from 5k to 10k.)

When I finally got it back I got permission from GK to fix it myself without voiding the warranty. What I found was a bad coupling cap feeding the horn amp. New cap...working good.

What I also found was the HORRIBLE work GK did. They replace an op amp, putting in a socket first and severely burned the circuit board.

They replaced a couple components on the power amp board, without removing the board. At the 4 solder joints for the two resistors they replaced, (which they tried to change out from the top of the board) there were big gobs of solder underneath, nearly touching the chassis.

I wrote a letter to GK describing the lousy work their "tech" did and sent close up pictures of the burned board, the solder blobs "dripping" from the board, and what I found that fixed the horn amp.

I was told they had a "soldering seminar" with all their techs, focusing on proper rework techniques and they added bench testing the horn amps at 5k as well as 10k.

They were apologetic, and even offered to replace the amp. The amp was working fine so I passed.

This episode soured me some on GK. People praise their repair dept. Not me.
 
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