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Hi Guys,

it´s been a while. I have been enjoying my Tweed Deluxe very much, but today I may have run into some trouble...

The last couple of weeks I noticed that the pilot light sometimes didn´t light up, or cut out after some time. It would turn back on again after unplugging the guitar from the amp, and plugging it back in again in one of the other inputs. The last couple of days the pilot light has been completely dead. (I had a couple of those lights fail on me already)

On top of that, today the VRM suddenly stopped working. The amp works just like it should, it seems like it´s bypassing the VRM. It may be that there is a little more hiss, but that may be my perception as well since I usually run the amp with the VRM up only 1/4 to maybe 1/2....

I don´t know enough about the VRM to confidently troubleshoot it, a couple of pointers from you guys to get me on the way would be very much appreciated (the same goes for the pilot light...)

Thanks

** BTW, do you still sell those amp cradle kits, Stephen ? How much would one be, shipped to The Netherlands ? Because I think the Tweed wil end up on my desk for some major overhauling I guess.....

Measure some voltages around the MOSFET according to this:

Here’s how it works: When the voltage drop across the MOSFET and the 5 ohm resistor is equal to the zener voltage the zener "turns on" and shuts down the MOSFET.
Ususally the MOSFET "Turn on" resistance is 1 to 3 ohms. So if it were to drop 3 volts and you had 600 ma of current flowing through the 5 ohm resistor, you would get 3V dropped across the resistor. The 6V dropped across the mosfet and 5 ohm resistor would limit the current to 600ma.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Thanks Stephen,

I´ll try that today, an report back.

Of course, you will be looking for the opposite. i.e. possibly something pushing the MOSFET full on.

Cradles are sold out for now.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Ok, that was quick.....

I opened up the amp and wanted to check if the vrm board was secure first.....As soon as I touched it with a chopstick the mosfet went up in flames (well sparks really)

I guess I'll be ordering a pre-made vrm board with you, Stephen. I decided I'll take apart the whole amp, and build her up from the start again. There are some things I think I can do better anyhow, so it's a good excuse...

I want to order the vrm pre-made so I can rule out any mistakes there. Is your price on the forum still valid ?

Yes.

You should try to resolve what went wrong. The rest of the amp was OK, no?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Yes, the amp was great. Except for the weird pilot light behavior mentioned a couple of posts above. In 2010 I think i went throught 4 pilot lights, and this last one was rated for 7V...

I´ll send you an email to order a VRM board today.

Thanks