I see Crate's Problem with the Palomino V32

[Mica]

Thanks again pdf64. One lasy question. Is there any compelling argument for using the full wave bridge over the single diode in this application?

[pdf64]

The voltage driving the fan will be a bit higher with a FWB, roughly 9V compared to 8V for a half wave / single diode.

[Mica]

[QUOTE=pdf64;230501]The voltage driving the fan will be a bit higher with a FWB, roughly 9V compared to 8V for a half wave / single diode.[/QUOTE

Rather then building a full wave rectifier can you recommend a commercial one? for example, I see this on Radio Shacks website:

1.4A, 100V Full-Wave Bridge RectifiersModel: 276-1152 | Catalog #: 276-1152

Would this work?

[J M Fahey]

Don't want to hijack this thread, but was forced to write, because I saw some dangerous info stated in the "Fender Fan" link mentioned.
They say "DC brusgless fans do not even need a rectifier, because they have one built-in"
Well, NOT SO, by any means.
Fact is, the NPN switching transistors driving its coils won't work backwards, thatīs all the "rectification" youīll find there.
Reverse connected transistors have a very low breakdown voltage, around 7V, absolutely unrelated to forward connected ones.
Passing reverse current, unlimited by a huge series resistor, (AC filament windings can provide *Amperes* easily) will result in Fan destruction, even fire.
I guess the poster just got lucky and his fan barely supported the 6.3V AC applied.
Bad engineering practice.
If he had connected 12VAC there (which according to his theory would work) would definitely have killed them, at once.

As of the bridge, a 1.4 Amp one will do nicely.

[Mica]

As of the bridge, a 1.4 Amp one will do nicely.

Thanks for the response, and the additional info/warning is appreciated. Do the preassembled bridges include a smoothing capacitor, or will I need to connect one across the output terminals?

[J M Fahey]

It's only the diodes.
I usually use a 1000 or 2200uFx16V there.

[pdf64]

Thanks for pointing that out JM, I thought it seemed a bit dodgy when I first read it, hence advising a rectifier.

[Mica]

So I hooked up the FWB that I referenced above (radio shack) with a 1000uF capacitor across the output terminals and I'm getting ~ 7.5 V out of it. I would like to get a bit more out of the fan. Can anyone suggest why I might be short of the expected 9V mentioned above (im also below the expected 8V that was suggested that I would see with a single diode).

Also, I did replace the 60 Ohm resistor that heats up the front panel with 2 30 Ohm surface mount resistors in series mounted to the chassis. This seems to have solved the heat problem on the front panel, but did nothing to lower the heat coming off of the back panel (I have the head version with the vent in the rear). It may have also made it a bit worse as the back panel now gets burning hot, either that or I never really noted how hot the real panel gets. The surface mount resistors are exactly 60 Ohms across where the one i removed comes in at ~ 63 Ohms. Could this decrease by 3 Ohms be causing additional heat in the rear of the chassis?

[J M Fahey]

7.5V is perfect.
Those 8 or 9V mentioned were "no calculator involved, top of the head" rough estimates.
You donīt want Hurricane Katrina blowing into your chassis, just renewing the air inside about once in one or two minutes, which *never* happened before.
Hands are very poor meters.
If you want to get scientific, stick a known good thermometer "in the air", over a little block of wood, in the approximate center of the chassis.
Let it sit there 10 minutes, fan off; then another 10 minutes, fan on; amp on, of course.

[soundguruman]

Crate makes the most unreliable amps in the entire industry.
Don't even bother to put money into repairing one. If you repair it, get it working...
it will just break again for another reason.

[Jazz P Bass]

Crate makes the most unreliable amps in the entire industry.
Don't even bother to put money into repairing one. If you repair it, get it working...
it will just break again for another reason.

Geez!!!
Can we get any more negative?
Lighten up.

[soundguruman]

Geez!!!
Can we get any more negative?
Lighten up.

There is no better advice I can give, based on 36 years experience repairing amplifiers...
Than to avoid repairing these amps, and put your money into something worthwhile. Buy something that will last.

There are a number of amplifiers flooding the market that are junk. Not only are you buying junk, repairing junk, you are taking
jobs away from American Workers. Time to forget about buying junk, wake up and smell the filaments.
Keep amp production where it belongs, in the UK and US, or other countries that respect human rights.

[J M Fahey]

If you repair it, get it working...
it will just break again for another reason.

Not like all other amps in the Universe, which get repaired once and then work FOREVER.
Thatīs what you are saying.

An talking about

There is no better advice I can give

why does that not surprise me?
Oh well.

[erjent]

Wow! I am blown away by this thread. Two and a half years running. Good job! My question is, and I hope I'm not of base, does anyone have schematics for a Palomino V50 212. It looks totally different from the 112. I need to change my tubes and was wondering about your thoughts on Tung-Sol, Mullard, JJ, or any other brands. Also my reverb tank broke. Any thoughts on a replacement?
Thanks in advance,
erjent

[Enzo]

Hi erj, welcome to the forum.

I would suggest you start a new thread for your amp, but I see you already have done so. We'll discuss it there.

Without me looking it up, are there numbers on your old reverb? And if the little inside wires broke off, have you tried repairing that?