Fender Deluxe Reverb Reissue (2002)

[PLF]

Not wanting to jump in on anyone's toes, but there are only three components in the bias supply: CR1, R69 and C36. Ah but which one failed and why?

Remove the 6V6's and get busy with your meter. Measure TP5, the junction of R69/CR1 and using the ACV range check the cathode of CR1.

Please see my response to 52 Bill above. It has all of the measurements I'm getting. I like your "Experience" quote.

[nickb]

Hi 52 Bill. Sorry to let this get so stale. My Father passed away and with the holidays, I wasn't working on much. At TP5 I get -155 mv. On the bias pot I get the following readings: Gray Wire = -168mv, Black Wire = -120mv, White Wire = -118mv. I think I had the pot turned all the way down for those readings. The CR1 diode tests AOK. C36 tests AOK. R69 has me rather bamboozled. The resistor that is in the R69 spot is a Metal Film type with a rating code of 0445 or 4.4M uf. It looks original and it tests 5.7 M uf. The specs are for a 22 uf Metal Film and they indicate that spec is required. Bias supply to CR1 reads 19.6Vac. Thank you for all of your help. I hope your holidays have been great!

So sorry about your family. There never is a good time.

R69 should be measured on the resistance range, not capacitance, and indicate 22 ohms. If this has gone open you would not be the first.

[Jazz P Bass]

Yeah, that 22 ohm resistor is there to act a a fusible element if problems occur.

The Flame Proof rating is so it doesn't burst into flame.
It will open in a charred state internally.

[PLF]

Bias voltage. Either there's none or what's there is insufficient. With output tubes removed, what voltage do you read on pin 5 of output tube sockets?

I get readings of -149.5 and -149.1 respectively.

[PLF]

So sorry about your family. There never is a good time.

R69 should be measured on the resistance range, not capacitance, and indicate 22 ohms. If this has gone open you would not be the first.

Good catch 52 Bill. Unfortunately, I misused the micro-farad symbol for the ohm symbol. I did measure with the meter in resistance range. What's weird is the R69 resistor is a Metal Film type with a rating code of 0445 or 4.4M ohms. It looks original and it tests 5.7 M ohms. The specs are for a 22 uf Metal Film and they indicate that spec is required. Bias supply to CR1 reads 19.6Vac.

[nickb]

Good catch 52 Bill. Unfortunately, I misused the micro-farad symbol for the ohm symbol. I did measure with the meter in resistance range. What's weird is the R69 resistor is a Metal Film type with a rating code of 0445 or 4.4M ohms. It looks original and it tests 5.7 M ohms. The specs are for a 22 uf Metal Film and they indicate that spec is required. Bias supply to CR1 reads 19.6Vac.

It sounds like R69 is open but the results you are reporting are confusing. The AC from the transformer should be more like 34 VAC so I'm not exactly sure what you are looking at here.

Try this. Make sure that your black lead is connected to ground. Note the chassis not NOT ground. I often use the sleeve of the input jack. Please report either the DC volts or AC volts (as specified) when measured at points 1,2,3 & 4 in this picture:-

[g1]

You need to replace that resistor. Don't let that 0445 code throw you off. I don't think it is indicating the resistance value.

[PLF]

It sounds like R69 is open but the results you are reporting are confusing. The AC from the transformer should be more like 34 VAC so I'm not exactly sure that you are looking at here.

Try this. Make sure that your black lead is connected to ground. Note the chassis not NOT ground. I often use the sleeve of the input jack. Please report either the DC volts or AC volts (as specified) when measured at points 1,2,3 & 4 in this picture:-

[ATTACH=CONFIG]37033[/ATTACH]

At last, I think I'm getting somewhere. Thank you for the input jack sleeve ground idea. I was attaching to the chassis ground. Using the input sleeve I get the following readings relative to your numbering in the picture. 1 = -156 DCV, 2 = -17.3 DCV, 3 = 17.24 ACV, 4 = -17.3 DCV. I have ordered a replacement 22 ohm metal film resistor and will let you know how things come out when I get it installed.

Thank you for your help!

[Enzo]

0445 is probably a date code meaning the part was made in the 44th week of 2004.

[PLF]

Success!

0445 is probably a date code meaning the part was made in the 44th week of 2004.

I finally received the 22 ohm resistor, installed it and the amp is fixed! I biased the power tubes at 47 VDC and it sounds great. Very quiet but a big rich sound. THANK YOU ALL very much for your patient help! It's been a real treat to have such great support and knowledge sharing. I learned a ton! You are all hero's in my book. I'd like to give a special thanks to Enzo, not so much for his clarification of the resistor coding, but for the many, many times I have obtained his help through others threads. I have repaired many amps through his guidance to others. Cheers to you all and thanks again.