Bottlehead Kits > Smash
Smash build with a few wonky resistance measurements (resolved)
FS:
Hello,
I have built the Smash in the stock version. Most of the resistance values were spot on. All the terminals with an asterisk (*) in the resistance check showed as OL on my meter. However, terminal 26 should be * but shows 0 Ohms. Terminal 31 on the other hand should be 0 Ohms, but gives an OL reading. Terminal 35 should be *, and showed up as OL in one reading, but then as 0.04 and slowly rising in another one. I tried to redo the soldering on the wires and components and re-flowed solder at the PT side for some terminals, but repeat measurements gave me the same readings. This can't be just a grounding problem, but I have painted the chassis and PT). The screws are tight. Thanks in advance for your help with troubleshooting. Cheers, FS
Paul Birkeland:
26 being 0 ohms means that the shielded twisted pair wires going from those terminals to the PC board, then to the sockets has an error. For some reason, it is extremely common for builders to switch a black wire and a shield wire along the way, and this will ground out the negative end of the filament supply.
For terminal 31, just tighten up the hardware on the power transformer a bit. If the tightening doesn't help, you can carefully remove the screw on that corner and scrape off a little paint under where it rests against the power transformer cover.
oguinn:
I had a similar problem on terminal 31. I took a Dremel with a grinder bit to it and it cleared things up.
FS:
Hi PB and Oguinn,
I have taken out the screws and sanded underneath the bell end and the top of the core. After re-assembly, terminals 25, 30, 31, and 36 are now properly grounded. I have checked the shielded twisted pair cable, and it connects all the right terminals. Colors are not switched. What should I read at the PC board? I have some troubles at terminal 26, had to re-solder a few times and it is still not OL, it reads 360 Ohms now, terminal 27 is OL.
Cheers,
FS
oguinn:
Is it 360 ohms, or 360k ohms? If it’s in the tens or hundreds of thousands of ohms it should be ok according to the manual.
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