The lytics on the Pre-Amp have increased but not by much.
Example: 47uf to 57uf, 100uf to 123uf.
I'm only looking at the left side since I am only having a problem on the left
side (no audio) but all the left channel pre-amp, driver, and power transistors
are showing good when tested out-of-circuit.
Could/would a thermal problem show up immediately, meaning in the time it takes
to turn it on and make a selection?
I picked up Anthony (Tony) Miller SHP amp book today, and started going through the checklist on page 39 for the driver/output section of the amp. A= 543...
To some it may seem like overkill but I have always replaced all the caps and all the transistors. When it comes to the power output transistors I replace...
took 3 tries for tom and I to fix one with a thermally intermittent pre driver [base lead would open] tom works on PA amps and I some time help him. tony's...
This is a very common problem !! Ron Rich ... From: armandh2646 <no_reply@yahoogroups.com> Subject: [Seeburg Jukebox Information Club] Re: SHP-3 Amp woes To:...
Ron, Which one is the very common problem? My aversion towards myself doing the repair, or that the SHP-3 needs to be repaired? I'm going to start with the...
Well, so far I've I knew what you meant, that was my poor attempt of a joke. So far the only thing I see as a problem on the driver board are the tantalum...
I figured that you were joking--at least half way--- Strange, I don't remember seeing the tants double in value--only open-- ? Ron Rich ... From: kc5tpa...
The lytics on the Pre-Amp have increased but not by much. Example: 47uf to 57uf, 100uf to 123uf. I'm only looking at the left side since I am only having a...
You got me lost know---you said the tantalum caps doubled in value, now you are talking the lytics--which are well within the "normal" range. Thermals can show...
Oops, sorry; wow what a misstatement. Searching, looking, reading, talking, and typing interfered with the 'tant' comment, they are fine. (1.07uF) I don't know...
I would not swap out all the small transistors-- Seeburg used real high quality transistors----guess I subscribe to the KISS formula. Ron Rich ... From:...
Ron, Well, what would be the KISS approach for no audio from the left channel of an SHP-3? Swapping inputs and outputs verifies both left and right inputs, and...
Chad, Easy for me since I have extra boards--first check the mute relay, then swap out boards to pin it to a board, then inject signal at various points on the...
Unfortunately, my equivalent to your KISS version of swapping out boards, is replacing suspected components, since I have no extras. My method is more of a...
Chad, I understand--did you test the small transistors--I sure would, prior to replacing all of them-- Ron Rich ... From: kc5tpa <cdstock@...> Subject:...
If I may add my 2¢, a good thing to have here is an audio osc. You can quickly go from stage to stage and find where the trouble is. A suitable audio osc can...
Duke, That usually works, and I agree it's a great way to do it, except on the SHP, it's hard to reach the lower (pre amp) PCB--Ron Rich ... From: Duke And Rat...
I did test them, and that is the problem, everything I've pulled and tested out of circuit is good. Which is leading me to the thermal issue. I'm going to wait...
typical parts testing will tell one if the parts are bad but not necessarily if they are good. parts that test good at 1.5 or 9 volts may break down under...
Well for those of you that have been keeping up, I've been waiting for parts to rebuild the left side of my SHP3, since this is the side that had no output at...
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