Again Troubles with Roland Bolt-30 - Dead/ Unknown parts

[52 Bill]

Sorry, my bad.

[Enzo]

SO start at the start. Are all power supplies present?

[loomis]

Ok I just quickly checked that looping the effects loop didn't solve the problem, and it did not.

I will begin probably in a few days checking voltages. I'll have to figure out what voltages I should be seeing on which pins of the 6L6's, unless someone can tell me real quick.

What I do not know how to do is check an OPT to make sure it's not shot. What do I do, send a few volts from my turned almost all the way down variac through the secondary and measure the primary somehow? How do I do that exactly? I'm new at that, so please give me a lot of details. Thanks.

[loomis]

Ok I have 505v on the plates and 0 on the screens and thus no output at all.

I've replaced (on the power supply board) D9 with an NTE5044A, and D10-D12 with 4007's. Recapped board as well.

I need to replace the RA-1SF diodes but I don't know a replacement. Anyone?

[doctor]

Ok I have 505v on the plates and 0 on the screens and thus no output at all.

I've replaced (on the power supply board) D9 with an NTE5044A, and D10-D12 with 4007's. Recapped board as well.

I need to replace the RA-1SF diodes but I don't know a replacement. Anyone?

You can use 1N4007.

[J M Fahey]

To be able to help you better please search and post Bolt 60 schematic.
D9/10/12 means nothing otherwise.
And why did you replace them?
First of all I'd check why no screen voltage .

PS: I'd start a new thread.

[Jazz P Bass]

Bolt 30/60 schematic.

[loomis]

Thanks Doctor.

Fahey, here's the deal, these amps' standby switch was wired wrong from the factory, and essentially just cut plate voltage. My standby switch was broken in the on position, which seemingly fried the tubes and also burnt up at least one of the diodes (D11) right off the PT on the PS board. It also burnt and lifted a trace completely, which I had to jumper.

PS tranny is fine afaik. It's just there's no screen voltage coming off the PS board to the tubes. I'm just going to replace the other 8 diodes and several resistors and the voltage regulator on the PS board. It has to be something on the PS board at this stage of repair afaik.

Thanks!

[J M Fahey]

Thanks Doctor.

Fahey, here's the deal, these amps' standby switch was wired wrong from the factory, and essentially just cut plate voltage.
My standby switch was broken in the on position, which seemingly fried the tubes

Yes, the schematic shows the same.
Nevertheless, it's a poor design.
Rewire it to cut all of high voltage to the right of Ra-C1 top.

and also burnt up at least one of the diodes (D11) right off the PT on the PS board. It also burnt and lifted a trace completely, which I had to jumper.

D11 may be shorted, why not?, but it's unrelated to high voltage problems.

PS tranny is fine afaik. It's just there's no screen voltage coming off the PS board to the tubes. I'm just going to replace the other 8 diodes and several resistors and the voltage regulator on the PS board. It has to be something on the PS board at this stage of repair afaik.

Don't needlessly shotgun parts.
You can make more damage than good, doubly so because most old Japanese Electronics still used phenolic paper PCBs , which are easier to damage.
And even if it were Epoxy/Fiberglass, still pamper it.
Yes, it most probably "has to be something on the PS board " but please troubleshoot instead of replacing parts at random.
Follow the tracks to see *where* you lose screen voltage, from D2/D5 cathodes, through R5/R6, up to the tube socket pins, including all copper in the path, both track and wire (and connectors, if any).
Only *some* problems mean "bad parts"; many come from bad connections.
You can replace *all* parts on that PCB and still *not* solve your problem. Sad but true.

[loomis]

Thank you Fahey. I will do so. I just looked at photo I took of the board and it looks like there's actually a crack in the board, which probably means cracked traces. Work is crazy, I'll try to look in the next couple weeks. Thanks!

[zeleni_paradajz]

Hello, i was wandering what replacement transistors did u use ?
Best regards!

[zeleni_paradajz]

Hello1 What replacement ransistors did u use? Best regards

[Jazz P Bass]

Repost of the schematic: Bolt 30.zip

[Jazz P Bass]

Hello, i was wandering what replacement transistors did u use ?
Best regards!

Nice name.

zeleni paradajza

Green Tomatoes.

[ilcaccillo]

Thanks Doctor.
My standby switch was broken in the on position, which seemingly fried the tubes and also burnt up at least one of the diodes (D11) right off the PT on the PS board. It also burnt and lifted a trace completely, which I had to jumper.

No it didn't, that caos was not caused by the standby switch being stock in the On position. It was something else.

You can always leave the standby switch in the ON position in any tube amplifier and it will not break anything.
Think about Hifi tube amplifiers none of them have a standby switch, neither any other tube equipment, just guitar amps because everyone copied Leo Fender.