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Yes, again according to SLM specs. SLM often did not connect the return braid of the coax cable to ground, hence it receiving its ground shielding from the tank chassis. SLM also liked to have parts common across its products. Hence if 79-214-02 reverb tank was the 'chosen', it got used in...

I was one of the very few PA area St. Louis Music repairman from the 80's to 2000's. It has been a long time since I have seen an Ampeg SS-140C, which is the predecessor to the VH-140C (they are essentially the same amp, sans a few changes in select components). I still have all the...

I find I occasionally make mistakes with the blocking holes ('cuts') or miss a small link.

You shouldn't have to isolate power supplies. For the Tone Vendor MKII: IC1, C7 and C4 should adequately isolate the positive and negative ground circuits. Since output jacks of many if not most pedals are tied to signal ground via chassis ground, that design has to be sufficient to allow...

Trace through your grounds and ensure your PNP style Tonebender has blocking caps on the input and output, as well as from circuit ground to chassis ground (which includes raw 1/4" jacks).

I am not familiar with the Hydra and there isn't a published schematic.

TY for the typo correction. IDK why I typed 15. At least I got the right resistor number!

Congrats! I was concerned as EPROMS are sensitive and do not standup to deviations. Since it is tied to the FV-1, I thought there was a good chance that would need to be replaced. If you want to expand your pedal to include the 7 effects inherent in the FV-1 chip, I believe I posted a...

If you look at the schematic there is a circuit which connects Q1's base to Q2's emitter and to its own collector. That is a negative (out of phase) feedback loop from Q1 to Q1 and a positive (in-phase) feedback loop from Q2 to Q1. If feedback is in-phase to the base, it adds to the original...

Lol. I think can answer a few of your questions: The potentiometer is a component of a resistance-capacitance high pass circuit. It is in parallel with a 470K resistor that both passes and blocks full frequency. The circuit with the pot allows there to be less resistance for higher...

I suggest keeping it simple and focus on 'Q' for more vowel, to which the Clyde McCoy circuit delivers. IMHO, that is the gold standard for a musical effect. Set the potentiometer gear so that the frequencies are more centered on the crossover point where the mids seem to 'jump' from low mids...

Ensure your clipping diodes are oriented correctly. It is hard to tell from the pictures. Ensure C3 is no more than 220pF. From the picture, it looks like one of those mini 1Uf poly types. If all else is the proper component, an A1M potentiometer will pinch out a bit more gain to drive the...

I've been repairing amps since 1977 and when I was doing it to make a little side money, I'd also quickly replace and charge the customer, for any suspicious part - just for time sake. I'd primarily do what you suggest for my own gear, given the plethora of good replacements (with some...

Tektronics 453A oscilloscope, Tenma 70-1055 DMM (hFE, continuity, diode, ohms, capacitance, etc.), Fluke 87DMM, Micronita 10-185. Simpson 260 and an EICO 666 Tube and Transistor tester.

Correct. The 'trim' has pretty much the function of balancing the symmetry using bias (think of the bias balance in a silverface Fender from the early 70's). I am trying to avoid driving the cost up for the client by throwing parts at it. Most people get upset when you tell them you had to...

Thanks. I am reading no shorts, proper forward voltage from E to B and C to B, plus proper reverse voltage readings. The reason I am interested in the gain measurement (hFE) is this and its PNP counterpart are responsible for initiating the push-pull of the larger transistors in the output...

I am battling a client's science project amp repair (1970's Sunn Beta Lead solid state), where I get proper signal right up to the inverter circuit, which is clipping on both half's of the push-pull and phase cancelling the output. Thus the amp output to the speaker is almost nonexistent and...

You want to measure the Vsd (voltage drop of the source referenced to the drain). I did that then adjusted to my ear and use, which is more like a limiter with gentile compression and some transients mixed in using the Blend function. If you have it squishing, that means there is enough...

A little lemon juice from a dropper will dissolve super glue. I'd continuity test the header before disassembling it. The common fail items on those inexpensive Amazon pedals are: - Jacks and stomp switches from casual use - Pots from getting dropped and the shaft breaking the internal...

Congrats on getting it well. I have one of these and it is a great pedal. Also cool to let your daughter contribute!