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Discussion Starter #1
Hey; Did a little job on a Koch Studiotone, had very low output, checked the usual stuff, Koch sent Jim a new op xfmr and he asked me to do it. The xfmr had it's own little board just to conn the wires. Anyone can solder, it's un-soldering that is tough...



Once that was done, the new one went in pretty easily other than having to heat the board to get it on.



Back in the chassis, it's working fine, played for about 1/2hr, leaving it on STBY for a bit and check it now and then. There was a diff in resistance of the pri windings of the new v/s the old, one side almost short on the old one, so yeah, it was the op.

Anytime you want it Jim, let me know first and you also left me with two pwr cords for that BTW...


:wave:
 

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I figured if you couldn't fix it we could just plug both power cords in and double the volume!:banana:

Merci Beaucoup ... now I can stop lugging that Orange to practice!
 

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Discussion Starter #5
Aren't PC boards a wonderful thing to work on?

www.claramps.com
Guess I have more exp working on boards than pt-pt. Takes a lot of patience and a good solder-sucker, (and a coffee, a smoke, and Classic Rock Big John FM).

Something I noticed on the Koch is that they use sockets for the op-amp IC's, nice, chips are a pain to remove from a board.

But you knew that already.

Wish I could find some more amps to work on.
 

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Discussion Starter #7
^^^^^^^^^^
For sure :food-smiley-004:

Thanks for the great pics also....I loves those amp innards.

Michelle...are you doing the amp repairs as a business or as hobby?

Dave
A thing of beauty for sure! I studied the board for about 1/2hr looking for cold-solder and trying to trace things, figure what was for what.

I do this as a hobby, would love to move towards a small biz but no VCR's or PC's, etc, only amps and guitars. Just need the time to set it all in motion.

And of course play in a band too! That's my retirement plan.

Terms: Cash or barter only, no fix - no fee, and some kind of 'guarantee', whatever :wave:
 

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Thanks Michelle...I hope you didn't mind me asking about the electronics hobby/business thing. A bit late for me to think of that now. My apologies if asking was not appropriate. You certainly write as though you are very familiar with electronics, amps, components, .....etc.

I'm slowly studying electronics as a hobby also, and hope to someday be able to focus much more time on it (likely after retiring, which is still a few years away).

Wild Bill has been a huge help responding to my emails about basic questions...mostly about amp construction concepts, components, etc.

Good Luck getting your business established (whenever you decide to try it)

Dave
 

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Discussion Starter #9
Thanks Michelle...I hope you didn't mind me asking about the electronics hobby/business thing. A bit late for me to think of that now. My apologies if asking was not appropriate. You certainly write as though you are very familiar with electronics, amps, components, .....etc.

I'm slowly studying electronics as a hobby also, and hope to someday be able to focus much more time on it (likely after retiring, which is still a few years away).

Wild Bill has been a huge help responding to my emails about basic questions...mostly about amp construction concepts, components, etc.

Good Luck getting your business established (whenever you decide to try it)

Dave
No problem Dave! Hope I didn't sound flip by saying 'whatever' I meant 'or something like that'. :smile: We put our experiences out there for everyone to view/comment. Thanks for yours.

I've been around electronics since I was a teenager, then I studied it and have worked in the telecom industry for 28yrs. Always enjoy working on things and just realized that is important to me, like playing, I use my talents and there's no reason why that shouldn't be profitable.

I was supposed to have the shop built this summer, oh well, all we need to do is partition the garage, new door, insulation, floor, etc. I have most of the tools and instruments I need. Minimumal start-up cost so almost zero-risk.

Bill really knows his stuff and is helpful to a lot here for sure, I've learned quite a few things from him. I still need to learn more about and do biasing and stuff.

Gotta go...:wave:
Michelle
 

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Thanks for the response Michelle...hope you get your shop finished soon...sounds exciting.

Dave
 
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