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Without a load the filter caps will charge to the peak voltage of the transformer output minus the voltage drop across the diode, which in your case should be about (17.8vac x 1.4) - 0.7 = 24.2 vdc. Pretty close to what you are measuring. Looks good to me. There will be next to no ripple...

As you increase the power supply capacitance, the on-time of the diodes in the bridge rectifier gets shorter and shorter, which increases the peak current that the diodes must conduct. I have no idea what the peak current demands are with the present power supply capacitance or even if it is...

This may shed some light: https://www.analog.com/en/technical-articles/output-voltage-noise-measurements-for-linear-regulators.html#

Very ambitious. My recommendation is to start simply, make one set of changes, such as power supply electrolytics, and then retest that it still works, but I'm sure you're doing that. With regard to resistor wattage, it's impossible to make a blanket statement that 1/4 watt are sufficient - it...

For mine, the FF and Rewind were inconsistent, I could see it was slipping. I've ordered a new idler tire and pinch roller for it.

That is a seriously nice deck. It's nice to see something done well, it looks great, works well, and was well made.

Streaming KJAZZ from Long Beach, CA, which I feed into my Ramsey FM transmitter so I can listen anywhere in the house where I have an FM radio or in my detached garage where I have my workshop. And any neighbor within 1/4 mile as long as they tune to 95.1 MHz.

Thanks. I'll give them a try.

Does anyone have a speed calibration cassette they'd be willing to sell? Making one myself would be like using your own voltmeter to calibrate itself. I'd be willing to buy a reference tone tape that someone made themselves from a good machine that is known to be true. I'm not looking to have...

Finally pulled RS-M85 off the shelf and gave it a go. I'm sure it hasn't been turned on since the 90's. Initially, nothing worked - couldn't get a tape to play, occasionally it would go into FF, but then I couldn't stop it - it seemed as if none of the switches worked. As Elite-ist predicted...

Just to finish up on what actions I took. Initially I bought one of the Delay-On Relays I mentioned in an earlier post. Cost about $30, which I thought was reasonable. And it does the job. It was easy to mount inside the PL4000, timing is easy to set, you can use either AC or DC for control...

Oh, and wired the meters to be after the DCP - no meter slamming. I have a delayed turn-on relay on order.

I have changed the timing of the DCP - installed a 100uF cap, which measured about 90uF - delays the relay click to about 5 seconds. A little short of where I wanted it, but sufficient. After a couple of beers & a single malt, I accidentally tested the DCP when I switched on the amp first and...

Any thoughts on using inrush current limiters, say 20 amp limiters? Could soften the blow to the switch & transformer. It'll drag out the time until those caps are charged, but I don't see an issue with that. Also, how about a zero crossing detector for turn-on? Might help to suppress the...

C2 & C4 were changed as were all electrolytics in the preamp. With the timing circuit engaged, once it times out and applies power to the op amp, the transient settles out in about 2 seconds. That is, the op amp settles in about 2 seconds. There is no dc on the preamp output once the...

Excellent point, I'll do that. Ha, ha. Don't sugar coat it, tell us how you really feel. It was indeed an attempt to mute the output on power up. There are notes in the service manual concerning "Excessive turn-off thump", where they recommend reducing the power supply capacitance (from...

Looks like this could provide a delay on function.

I agree with you Don, but it's the lessor of two evils. Wasn't the relay in the PL4000 made to switch the PL400? Or the PL700? I could put up a placard stating: "Turn on: Turn on PL4000 first. Turn on PL400 second. Turn off: Turn off PL400 first. Turn off PL4000 second." As I said...

I should have mentioned that as built C10 was a 100uF capacitor, not 470uF as shown on the schematic. This gave a timing of about 9 seconds. I changed it to 220uF to extend the time. You're right, but just. Tests that I conducted this morning, the DC transient was essentially over in a...

I thought of that, but it would have to be less than 3 seconds, that's not enough time for the preamp to stabilize.