Dumble - help needed urgently!

[jelle]

Hmmm, I just traced the layout and I do not see anything wrong with the layout. This amp is a Bluesmaster with Midboost, Megaboost and Channel select on three different relays.

It seems that there may be an issue around the Channel select relay. Without a scope, it is hard to see where the signal stops. It seems that the output of V1b is shunted to something it does not like. Hence hum.

Also, I will get flak for this, but how much hand holding should a kit seller provide at a given price point? It cannot be endless, that would be a non sustainable business model.

That said, the layout is a really clear one. Something failed.

[Mousey Dung]

Is it possible that you have the blue wire from the master volume pot that is drawn as passing underneath the middle relay, actually *connected* to the relay, other than at the point where the wire terminates?

Just checked -- no, it's going from the Master Vol to the top of the orange 10 nF cap.

[ToneMerc]

Hmmm, I just traced the layout and I do not see anything wrong with the layout. This amp is a Bluesmaster with Midboost, Megaboost and Channel select on three different relays.
.

Jelle, third relay has a hi-freq trim control that is triggered from PAB relay so that its only active in that mode.

TM

[ToneMerc]

Is it possible that you have the blue wire from the master volume pot that is drawn as passing underneath the middle relay, actually *connected* to the relay, other than at the point where the wire terminates?

Just checked -- no, it's going from the Master Vol to the top of the orange 10 nF cap.

At the OD relay did you install the very small jumpers across the NO and NC contacts at the underside?

TM

[jelle]

I looked at this one, did not see the HF taper on OD?

http://brownnote.net/BMKIT/BMK-V2.jpg

[ToneMerc]

I looked at this one, did not see the HF taper on OD?

http://brownnote.net/BMKIT/BMK-V2.jpg

That's not the version; he has the one with all the bells and whistles, integral relays, HF trim and soul control.

TM

[drew]

So, the 8 trimmers are:
OD
PI
HRM (3)
HF
"soul" -??
?

[Mousey Dung]

Hmmm, I just traced the layout and I do not see anything wrong with the layout.

There's absolutely nothing wrong with the layout apart from the wiring to the PAB switch being wrong, and the lack of information on how to wire the AC, or to dasiy-chain the tubes, etc.

Also, I will get flak for this, but how much hand holding should a kit seller provide at a given price point? It cannot be endless, that would be a non sustainable business model.

You're right -- I'd be the first one to give you major flak for not making provision for the full details of the situation. There was plenty of communication prior to sale and during the shipment. This was followed by broken promises about providing documentation, no documentation, inappropriate documentation, no identification of which parts generally go where, there were duplicates, missing parts and mismatches, there was no terminology list to help identify major sections, no step-by-step instructions, etc. The seller sold me the kit fully knowing my circumstances, then proceeded to not provide crucial info at the critical stages..

That said, the layout is a really clear one. Something failed.

I'm hurt by the insinuation. It might be me, it might be a tube or a relay...

[Mousey Dung]

At the OD relay did you install the very small jumpers across the NO and NC contacts at the underside?

Yes, but you may have helped locate the problem nearby. Are both ends of the diode at the OD relay supposed to be connected to the coil?

[ToneMerc]

I looked at this one, did not see the HF taper on OD?

http://brownnote.net/BMKIT/BMK-V2.jpg

I was incorrect, his layout the trim is on the PAB relay path looks like.

TM

[jelle]

Sorry to hear that the communication with Moss did not meet your expectations. This is a very complicated amp for a beginner to build. I would argue that it is too complicated as a kit build for the public.

That said, the layout is a really clear one. Something failed.

I'm hurt by the insinuation. It might be me, it might be a tube or a relay...

Well, I am trying to help you here, otherwise I would not be spending my time posting here. The comment is not a personal one. This is a technical issue, don't you agree?

Let's test something. With the amp on, but is standby mode. Set Channel select to Clean. Test if:
- the OD input is grounded,
- there is continuity from the decoupled side of the .01uf CL2 cap to the 220K resistor at the efferts loop.
- what is the resistance from the decoupled side of the .01uf CL2 cap to ground?
- Is there a DC voltage on the decoupled side of the .01uf CL2 cap?

[ToneMerc]

At the OD relay did you install the very small jumpers across the NO and NC contacts at the underside?

Yes, but you may have helped locate the problem nearby. Are both ends of the diode at the OD relay supposed to be connected to the coil?

Yes, that "flyback diode" should be across the relay coil and verify that you have the small jumpers at each relay.

TM

[martin manning]

All three relays should have a diode connected across the coil, with the banded end connected to the the positive side. It's not obvious from the layout how this is done, except for in the case of the right-most (mid) relay the diode is soldered to the eyelets. The chatter you are hearing is likely a relay, I don't know what else it could be.

[Mousey Dung]

At the OD relay did you install the very small jumpers across the NO and NC contacts at the underside?

Yes, but you may have helped locate the problem nearby. Are both ends of the diode at the OD relay supposed to be connected to the coil?

Yes, that "flyback diode" should be across the relay coil and verify that you have the small jumpers at each relay.

TM

Okay, double-checking. Please see pic below.

[martin manning]

No and No. The diodes connect from the red relay supply lead to the control side of the coil. The non-banded end can go to the eyelet as you show it, but the banded end has to go to the red lead.