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Post by e093116 on Mar 27, 2017 13:40:10 GMT
Hello,
I spent some time over the weekend hooking up the subject consolette to an STD160 phonograph. Aside from a few minor issues that were easy fixes, it all works good with the exception of the volume control. I can get sound out of both speakers when on the soft setting, but only get sound out of the right speaker when on the loud setting. I am assuming the problem lies on the volume control circuit board, but haven't found any bad components or bad (loose from the board) solder joints. I have the full 10 wire hookup and everything seems to work great except for this last problem.
I've noticed there are manuals on ebay...installation, parts, and service. Can anyone offer any suggestions as far as correcting the problem and/or advise which manual would contain a schematic for the volume control board? The service manual on ebay covers up to DEC225, I'm assuming this is where the schematic would be found and that the board is basically the same in all versions. Can anyone confirm?
Thank you,
Bill
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Post by Ron Rich on Mar 27, 2017 14:24:59 GMT
Hi Bill,
The DEC-3/4's have a different audio system from the earlier DEC's. Check the FAO's above for "legitimate" suppliers of service manuals, and I'm sure you will find the correct service manual. Ron Rich
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Post by e093116 on Mar 28, 2017 16:00:42 GMT
Ron,
Thanks for the tip on the audio system differences.
I spent some more time on this last night and noticed that there was a high resistance (~225 ohm) between the loud switch contact and one of the relay contacts in the circuit in question, which was curious since the only thing in between was the circuit board trace! I remelted/resoldered the connections on both ends without any improvement, so then I installed a jumper wire. I'm guessing that one of the solder pads on the board must be partially lifted/broken or something (I didn't remove the solder to inspect). I'm sort of surprised by the failure mode and that it wasn't a "hard" open, but it also looks like someone was "in there" before (the plastic cover for the relay was cracked in a couple of places), so who knows what really went on previously.
My last "problem" is to rebuild the PRVC motor, the motor spins but doesn't always drive the volume pot. I just need to get around to replacing the green pad on the motor...besides being worn it also appears to have been "oiled" by a previous na'er do well!
Bill |
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Post by Ron Rich on Mar 28, 2017 16:13:53 GMT
Hi Bill,
Glad you found that ! On the PRVC4--it sounds as if you have a code A motor assembly. I would attempt to remove the oil from the green pad, SLIGHTLY stretch the large spring and make sure the VC itself turns without binding--You can oil the VC itself at the point the shaft enters the control--this sometimes "fixes" that problem-- Ron Rich
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