2nd Gen Build Started (that didn’t take long…)

[Raoul Duke]

I’m about to wire in the power cable and wanted to check if there’s anything I may not know about doing it correctly - this being my first non-IEC type build. Here’s what I know:

- Hot/black should be fused (going to the tip of the fuse holder)
- Ground/green should be the longest wire so that if the others pull, chassis doesn’t go live
- Neutral/white will be spliced to white from PT and relay PT (I’ll use the lineman’s splice)
- “Comfortable” slack in the black and white wires so that they aren’t already stressed inside the chassis
- Trim back the insulating jacket so that apx 1/2” is inside past the strain relief grommet

Any other tips I may not be aware of?

Thanks!

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[martin manning]

That pretty well covers it. Earth ground (green) should be on a dedicated bolt. Without a ground switch or courtesy outlet to serve as a tie point, the neutral has nowhere to land if you follow the best practice of fusing and switching the line lead.

[Raoul Duke]

Thank you Martin - I appreciate the QC!

[Raoul Duke]

Ok,
I think I have everything wired for the smoke test. I’ve spent the last half hour tracing each wire and looking at solder joints with a magnifying glass. Everything appears to be in order. Anybody see anything I might have missed or should change?

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I’ll be reviewing my 102 smoke test next just to reacquaint myself with what I’m doing and trying to accomplish.
Hopefully today or tomorrow I’ll light it up.

[martin manning]

I can't really see all of the primary wiring, but I think you are ready for a test. Remember, low wattage bulb in your limiter, and no tubes installed until you have bias voltage on the tube sockets, and a load connected to the output. That will come later. The first test is just to see if you have all of the power supplies working.

[Raoul Duke]

Here’s the primaries:

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[martin manning]

Looks ok to me.

[Raoul Duke]

Smoke test results, all voltages unloaded:

- Limiter flashes as expected, low glow in ON/OPERATE
- No smells, smoke, noise

AC in through fuse, switch to transformers: 100vac
Relay trans at regulator out: 17.1
Relay board in: 17.1
DIN from relay PS: 17.1
Rectified HV: 396
Bias Supply: 45.7vac
Heaters: 5.2vac
B+1, 2, 3: 396
B+4: 393
B+5: 391
Caps all discharged below 1v within 2-3 minutes.

My uninformed instinct is that everything looks ok, but the relay voltage seems high?

Thoughts and opinions welcomed!

[martin manning]

B+ voltages look good. Bias supply voltage should be negative DC (?). Didn't you have a very similar reading anomaly on the reg in/out on your 102? 17VDC in sounds reasonable, should be 12VDC out. It was a meter range setting issue, wasn't it?

[Raoul Duke]

Oops, yes - just re-checked it and it’s -42.7 at the bias pot.

The relay drops to 8.4 at the small relay board when the Man/Ped switch is in Manual, but stays at 17 otherwise (both in and out).

I also don’t hear the relay “click” on power up/down - but I think that’s normal because this relay is wired differently than the 102 relays, correct?

Thinking my regulator isn’t regulating - pull the board?

[martin manning]

The relay supply voltage stays at 17 AC or DC?

[Raoul Duke]

DC

[martin manning]

So the regulator is doing nothing, same 17VDC in and out? Check that the connections are as drawn in the recent 2nd Gen files post. Maybe pull that board out and inspect.

[Raoul Duke]

I think I found the problem. I forgot to remove the jumper that connect pins 1 and 3 on the relay PS board - so the regulator was bypassed from what I think I know.

Should have the PS board back in in a few minutes and we’ll see if I found the problem.

[Raoul Duke]

Umm…. Yeah… I forgot to remove the wire; you know - the one with the “X” through it.

Long story short - problem solved. 18.4 in, 11.8 to the relay and the DIN. Drops to 5.7 when the switch is in Manual.

Onward to the PI…