Recent content by sweetbeats

Yes. Sorry about that. I updated the post. Yeah that’s essentially it. And it’s not just using the +6V rail as a messenger at power-up, but also power-down, because impulse voltage happens in both cases and could thump the outputs either way. It’s no different than my power conditioners I have...

Thanks. The 1N4006 parts are indeed overkill for D801~805, but there’s no harm in it. Use what you have for those parts. D806 is different. D806 provides for that reverse-flow of the timing circuit at power down immediately breaking the circuit to ground for the muting relays’ coils and...

I’m not sure what your numbers mean…590, 240, etc. Depending on the tester, diodes should read a given voltage in the forward direction and zero in the other. Regardless, it’s best to test diodes out of circuit. I would not be going hog wild on all your diodes. I recommended shotgunning the...

There are more things to test besides capacitance. ESR is another. But, look…those caps are over 40 years old. And these are not caps that were manufactured like some of the high-quality computer-grade caps that are found in the power supplies of like my Ampex and 3M machines that are...

Recapping typically only refers to the electrolytic caps; typically no need to replace any of the non-electrolytic caps unless there’s a known fault involving one. I’m not familiar with F&T caps. I use Nichicon, Panasonic, Vishay/Sprague, Cornell Dibiloer or Mallorey. 105C yes. On the diodes...

You can’t test caps in circuit.

I am not either. I consider myself an advanced hobbyist. I do my best not to get others in trouble. And FWIW, on your case, I’ve probably ready that segment of the Theory of Operation 4 times, and throughout our correspondence been in the schematics at least a dozen times. Notice it wasn’t until...

I would actually consider 6MOhm open circuit. That is very high resistance and the fact you have something measurable when the system is powered down is likely only because of some stray path to ground when components are not in their powered state. The bottom line is, after a few seconds, there...

Don’t strap pin 3 J171 to chassis ground…strap it to the power rail’s 0V reference on pin 2. The power mute timing circuit on the power supply PCB doesn’t “share the same rail” as the +6VDC lamp power rail per se, but, yes, there is association. As I stated earlier the timing circuit uses the...

You may or may not hear any mechanical noise from the muting relays. It depends on the relays. So I wouldn’t focus on that mechanical feedback. I don’t know what’s mounted. What happens if you ground J171 pin 3 and power up? Prepare your monitor system for a power thumb beforehand. Does audio...

So, my apologies, I was looking at the circuit backwards…the circuit on the power supply PCB doesn’t power the mute relays, it delays continuity to ground for the relay coils…so one side of the coils should be seeing +24V all the time. When you power up the circuit on the power supply PCB delays...

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Okay. Stay tuned on the rest.

I think what I have for you as far as fader knobs is the three aforementioned correct M-300 series input channel putty/blue parts, and a couple dark brown with orange stripe. The alternatives I have are either going to duplicate colors over in the master section, and that doesn’t make sense to...

Okay…let me go shopping in storage and I’ll follow up with a private message to you. I do know I only have three of the fader knobs left in that color scheme (putty/blue). I have 8 of the group section orange with blue stripe, and an assortment of other color schemes from other models (exact...