Fender Princeton

[The Dude]

Boy, it's a good thing for Bernie that there are so many medical professionals here.

[g1]

We know Bernie's got the good stuff anyway. And lot's of experience as a Case Manager.

[Enzo]

I am at the moment enjoying a medicinal amount of Georgia Moon corn whiskey. It seems to be helping.

[bsco]

I'm told alcohol works good for aches and pains, Bernie.

hahahaaa...yeah..I know.....I have to wait until I finish these pills I have to take first....it has been almost a month since I had any beer....there will be a breakout happening real soon...

[bsco]

I am at the moment enjoying a medicinal amount of Georgia Moon corn whiskey. It seems to be helping.

I would say that it is...hard liquor is something my system cannot physically handle...it makes me very stomach sick. and I can't stand the taste......so I usually pick up a two four case of light beer...there was a time when a 6 pk would suffice......not anymore.....

[bsco]

Boy, it's a good thing for Bernie that there are so many medical professionals here.

yeah....who needs a doctor when I have all you fine people...lol.....

[bsco]

And edibles, which are perfectly legal here now.

I am old fashioned I guess. I either roll it or use a pipe....which reminds me...I have to top up my stash after the weekend....it is 2 AM here and I am going to fire up the pipe....and watch some repair videos on youtube....you can only sleep for so long....xraytonyb and Mr.Carlson's Lab are a good choice....have fun everybody....I will get back at the amp tomorrow....man..it is soooo good to be retired....

[bsco]

back to this repair....>i checked the caps...all good except for the one I had previously mentioned..I also replaced the bias diode and cap.....1N4007 and a 100uf/100v cap...and one 25uf/25v.....that's it......not sure what the bias is supposed to be set at.....I will leave the output tubes out while I check the voltages to the output tube sockets....i'll have to do a google search for a schematic....by the way..this has the death cap...if memory serves me correct just cutting it out should be ok??just noticed..there is no bias pot in this...is the bias voltage -40V?? I assume it is fixed??

[g1]

Does this amp have reverb? 2 prong plug, or 3?

[The Dude]

There are different flavors of Princeton amps. It might help get everyone on the same page if you could link or upload a schematic of the amp you are working on.

[bsco]

Does this amp have reverb? 2 prong plug, or 3?

it has reverb and tremelo,,2 separate reverb cables...

[bsco]

There are different flavors of Princeton amps. It might help get everyone on the same page if you could link or upload a schematic of the amp you are working on.

I don't have one yet...I'll get one and post it up...you say there are a few variations....

[Leo_Gnardo]

this has the death cap...if memory serves me correct just cutting it out should be ok??just noticed..there is no bias pot in this...is the bias voltage -40V?? I assume it is fixed??

Snip snip death cap be gone. Bias is set by resistor paralleled to bias filter cap. You can alter the value of this resistor to suit the tubes in the amp or add a trim pot plus fixed resistor combination then you can dial bias to your heart's content. ALSO be aware the 100K resistor typically installed in series with the bias rectifier sometimes drifts & changes value. Worth checking and if it's far off the mark, replace it.

G1's 2 or 3 question refers I'm sure to Princeton's AC line cord. Grounded or no? If not, for safety's sake it oughta be the modern 3 wire cord & plug.

[bsco]

Snip snip death cap be gone. Bias is set by resistor paralleled to bias filter cap. You can alter the value of this resistor to suit the tubes in the amp or add a trim pot plus fixed resistor combination then you can dial bias to your heart's content. ALSO be aware the 100K resistor typically installed in series with the bias rectifier sometimes drifts & changes value. Worth checking and if it's far off the mark, replace it.

G1's 2 or 3 question refers I'm sure to Princeton's AC line cord. Grounded or no? If not, for safety's sake it oughta be the modern 3 wire cord & plug.

it has a 3 prong cord....looks like factory with the red ac plug at the end....I'll check that resistor as well.....I can check the PI coupling caps simply by pulling the output tubes and measure for a leaky voltage where they connect to the output tube grid pins....only one cap bad....bit i also replaced the bias cap and diode..trying to find the correct schematic...

[bsco]

lets see if I can get this schematic posted.... Princeton-Reverb-B1270-schematic1.pdf