Search results

The silads need to be intended for a TO3 transistor package.

If it's truly rated for 110 volts it's probably also rated for 50Hz. At 60Hz/120 VAC it will be fine.

Power supply could be improved with 7812 & 7912 (+/- 12V) regulators. If the raw DC voltage with about 110 VAC input is above 15 volts, the 12's will work ok. I used these in a TO92 package on my 3300 preamp. Built them on perfboard a little bit larger than a postage stamp. Ebay now has PCBs...

I wouldn't tear apart a good power supply. Most people have a wall wart power supply lying around that is a 6-12 volt output. You can look at line voltage without a transformer. Assuming your scope has a 3 wire power cord you lift the ground wire on the power cord. Not the safest thing to...

I have some phono jacks that were used on the P/L 4000 etc. If interested send a P.M.

Clicks and pops when switching suggests a DC offset from the source.

Lead free solder sucks. Been there, dealt with the aftermath.

Is there a schematic available? The 3 transistors likely control the 3 relays.

Does this thing just turn on outlets in a sequence? If so it seems awful complicated. I could do that with a 555 timer and a counter chip. Multi stage linear filtering? I hate to rain on a parade but it sounds like gobbledygook marketing to me. A ferroresonant transformer will beat the...

..and Nav's And Nav's photos.

I wouldn't touch her with a 10 foot pole. I'd use my hands. I wouldn't touch a 4000 with anything. 100's of cracked solder joints on I/O jacks and mother board.

I've seen him 3 or 4 times. The last was at a roller rink in Toledo, Ohio.

FWIW, I visited the Slovenia KRSKO nuclear plant a few years ago.

I'm not a fan of the shotgun approach of the repair kits. Too many opportunities to mess things up. Replace only what has failed.

If I understand the proposal, the R/C network is in parallel with the speaker. Assuming the speaker is largely an inductive load, the added snubber would effectively appear as a net resistive load back on the amplifier during normal operation. I must be missing something as I don't see the...

Yep, did not make the weekend get away in Israel.

By the way, anybody that wants to know anything about relays should look up Rod Eliott’s article on his Elliott Sound site. Like all oh his work it’s very well researched and presented in a manner most anybody can understand.

First of all, thanks to all for the nice comments. Yes, the P.L tech manuals I’ve shared have ended up on a few other sites. I didn’t write them and don’t have legal rights to them. I was fortunate to get approved as a P/L service provider in early 1984. That brought all of the service manuals...

The configuration of the contacts may seem confusing at first glance. However it adds additional speaker protection that most other designs don't consider. The schematic is attached for convenience Relay contacts are provided in 3 classes. Normal is defined as shelf state/de-energized. N.O...

Attached is the original schematic along with the new version for comparison. It appears to me that the new version has what I assume to be the volume control (R30B) after the buffer and therefore in series with the output. It's entirely possible I'm wrong. If so kinfdly point out my error.