Dhouse7516
New member
I reflowed all of the Breg pads, the +reg pad, and the pad at the other end of the R4 on the B side, and I am still getting the same voltage readings as posted above.
Failed Final Voltage Check
- Thread starter Dhouse7516
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Dhouse7516
New member
I also tested at the R4 pads, and they are good at 219K ohms.
Is the jumper leaving OB well soldered on both ends?
The 6V cathode 288V on the plate to me seems like the regulator on that side just isn't connected somehow. Also be sure the 431 regulator is there and not an MPS4250.
The 6V cathode 288V on the plate to me seems like the regulator on that side just isn't connected somehow. Also be sure the 431 regulator is there and not an MPS4250.
Dhouse7516
New member
The 431 regulators are both in the right place. I will double-check the OB jumper tonight. Thanks.
Dhouse7516
New member
Well, I stepped away for a bit and then took another shot at this. I reflowed all the D-Socket and shunt board joints and reconnected the board above the D socket. My measurements are below. I suspect that I may have damaged one of the traces on the shunt board. I hate to admit defeat, but I might need to send it in to y'all. Let me know if you have additional suggestions. Thanks much.
IA: 290
IB: 289
OA: 282
OB: 155
KregA: 6.41
KregB: 4.5
IA: 290
IB: 289
OA: 282
OB: 155
KregA: 6.41
KregB: 4.5
Typically that set of voltages would have me double checking that the wiring going to the 9 pin socket is all routed properly. If you swap a pair of the wires going between that board and tube socket, you can end up with wonky voltages like this.
If you are unable to remedy this issue, you can contact queen(at)bottlehead(dot)com about ordering a repair service. Be sure to send her a link to this thread so she knows we have worked on the problem here.
-PB
If you are unable to remedy this issue, you can contact queen(at)bottlehead(dot)com about ordering a repair service. Be sure to send her a link to this thread so she knows we have worked on the problem here.
-PB
Dhouse7516
New member
Yep, I triple checked all of those wires, and reflowed the solder for all of them. It's all good. Are there any issues on the board that you can think of that might cause these voltages? Anything I should focus on in particular? I've confirmed that the regulators are in the right place, reflowed the solder to the R4, and confirmed that BREG is connected to +Reg. Is it possible I have a defective or damaged regulator? I tested the resistor and it measured fine.
A defective regulator will typically short out and you'll see 1.8V or so on Kreg and low OA or OB voltage.
Dhouse7516
New member
Got it. When you said above that the cathode and plate voltages caused you to think the regulator wasn't there, it made me think that a defective regulator could also cause the voltages. Anything else I should focus on?
Dhouse7516
New member
So the red wire connecting the B side of the shunt regulator to 28L just snapped off at the BReg joint as I was lifting the board to re-check my wiring. I'm guessing that it got damaged with all the fiddling I've been doing. Would that cause the voltage readings I was getting (if it wasn't properly connected to the board)? In any event, I will replace it and see what that does, once I can find some wire. It's 22AWG, correct?
A broken wire could cause some issues, though one wire is unlikely to cause all of what you're seeing.
-PB
-PB
Dhouse7516
New member
Okay, thanks. I am at a loss. I went back over the board and the tube terminals again, re-flowed a couple of additional joints, replaced the shunt board wires and am still getting very similar readings:
IA: 284
IB: 285
OA: 280
OB: 152
KREG A: 6.38
KREG B: .45
Unless you have any additional thoughts, I will reach out to the address you provided earlier and request a repair. Please keep me in the loop as I really want to know what the issue is here and learn from this! Thanks for all of your help.
IA: 284
IB: 285
OA: 280
OB: 152
KREG A: 6.38
KREG B: .45
Unless you have any additional thoughts, I will reach out to the address you provided earlier and request a repair. Please keep me in the loop as I really want to know what the issue is here and learn from this! Thanks for all of your help.
Dhouse7516
New member
Paul, as I was going back over the board just now, I noticed that the R3 resistor on the B side has a large crack in the end. I tested it and it's bad (no resistance). If you think that this might explain the issues I'm having, I'll order another one and replace before sending in for repair. Thanks.
It certainly wouldn't hurt to give that a try.
Dhouse7516
New member
Thanks, I assume this is a suitable replacement?
https://www.digikey.com/en/products/detail/stackpole-electronics-inc/RNF14FTD2K49/1706690
https://www.digikey.com/en/products/detail/stackpole-electronics-inc/RNF14FTD2K49/1706690
Sure, that will work nicely.
Dhouse7516
New member
Thanks, Paul. I need to order some additional single-core wire as well. It’s 26awg, correct?
22 AWG solid is recommended. The kit should have come with some extra wire.
Dhouse7516
New member
Thanks, I used up the extra when I was re-wiring the D socket and the board
Dhouse7516
New member
I received the replacement R3 resistor today that we discussed above. It's physically smaller than the one supplied with the kit (see picture). I assume that's because it has a different tolerance or wattage. Maybe a dumb question, but do I need to be concerned about this? Do I need to replace the A side R3 with a matching resistor (I bought two) as well as the B side, which is the one that is damaged? Thanks.
