Deluxe Reverb RI bias question

[pontiacpete]

Looks good so far. You know you could try reading the current by measuring the voltage betw CP14 and pin 3 and divide by the resistance of each side and see what you get. V/200.3 = I current

[MWJB]

"Yea, I am looking for a drop in replacement with costs down. Tech in area has not returned emails or phone call as yet. May give him another call/send another email this morning. I may be doing this myself if tech does not call back, and you guys are pretty sure of the part that is defective."

Whoa! Slow down. Your dc resistance measurements do not indicate that there is definitely a problem, certainly not enough evidence to warrant a new OT & stripping the old one out. Get your 6V6 tubes, try them in the Righthand socket, do any of them work?. If not, measure dc voltages at pins 3, 4 & 5 (use meter leads with clips, make all connections with the amp unplugged from the wall), look for any carbon tracks around the tube socket that may have been caused when the fuse blew. You do not want to buy a new OT if you only have a blown screen grid resistor, or a duff tube socket....otherwise you will still have the same problem when the new OT is installed.

I don't care about the condition of the paint on the 6V6 tubes, or when they were made, or even what brand they are...none of that matters, all that matters is that they are "reasonably" matched on idle bias current.

[Newguy]

Looks good so far. You know you could try reading the current by measuring the voltage betw CP14 and pin 3 and divide by the resistance of each side and see what you get. V/200.3 = I current

Pete

I assume there is no current, that is the problem. That socket is not working it appears. The tube in the socket does not get hot. I left the amp plugged in and turned on last night for about 3 hours (by mistake, was doing other stuff). Amp still works the same/sounds the same as it did a couple days ago.

MWJB let me know if you want me to do what Pete has brought up. If so I need more details I.E. (answer to number 2 below).

1. Pin 3 of each tube (black probe) and (red probe) to CP14.
2. I assume I set the meter to vdc?

No problem doing this but I need meter settings.

[MWJB]

"The tube in the socket does not get hot." Confirm that ANY tube put in that RH socket does not heat up...if you are only putting one tube in that socket you can even try a 6L6 if you have one around. There should be some warmth due to the heater circuit, but the plate current dictates the majority of the heat. When probing pins 3, 4, 5 you are looking for dc volts, use the highest range on the meter. To do Pete's test, you use the same: dc volts, highest meter setting.

[Newguy]

MWJB/Pete

Thanks so much for your help.

I just got in contact with the tech here local. I am going to take over to him this morning as I think it is better to have a real tech go over this from top to bottom.

Thanks so much for your time guys. I will update this thread when the tech tells me what he found.

You guys have been great.

[Newguy]

Took it into tech today. He had room in his house set up for guitar and amp repair. Looked to me like he had all the right equipment. I was on way home about 10 minutes from tech, and he called and said it was a screen resister. May get it back today if he has resister in stock.

If this works out I will be one happy man. I do not like working on my own amps but on the other hand, I do not like taking my musical equipment to typical music shops that are not known to do good work.

Can't wait to get amp back to see what it sounds like with both tubes working

Finding a good tube amp repair tech is like finding a good mechanic that you can trust...it don't happen often

[Newguy]

Got amp back today, after tech only had it for a few hours.

Two screen resisters were replaced. One was bad causing the problem, and the other he replaced as tech said they get hot and since replacing one and had amp apart, he replaced the second one while he was in there.

He took the time to read through this thread and because amp was blowing the spec 2 amp fast acting fuses (only when switched to standby mode for a couple minutes after playing..go figure), the rectifier tube needed replacement also. He thinks this happened when I shorted the amp out putting meter probes in the wrong spot.

I brought some tubes with me as he said he had a tube tester. He tested two sets of 6v6gt tubes for me as well as a backup rectifier tube. One set 6v6GT (orig Fender) were strong and very close match. The other set of 6v6gt tubes were strong, but not matched well. He also tested rectifier tube. He said 6v6gt in amp tested very strong and very well matched so he used those.

For troubleshooting and fixing the amp he charged me $25, including testing tubes. My extra rectifier tube was used as replacement. Best $25 I have ever spent. I threw in another buck for the two resisters.

I will scan his card later in case any one in the East Tennessee area is looking for a tube amp tech. Just found his website link, so I will not scan his card:

Willy Guitars

He is a pretty good guy and easy to talk to. Hope this can help some one in the area if looking for a tube repair guy. I have lived here over 10 years, and have not heard about any tech/shop that people thought were all that good. The answer I kept getting was Nashville (6 hr. drive), and Asheville N.C. (2 hr. drive). West Knoxville is 30 min. drive for me.

I am sure there must be some other good techs in the area, but I just have not found them

Amp sounds fantastic..even better then running on only one tube

Thanks all on forum for you help...especially MWJB

[pontiacpete]

That's great to hear you got your amp fixed, Newguy, and for such a low price!!

[Enzo]

Just to humor me, ask him if the screen voltage was missing from the cold tube.

The screen is pin 4 of the tube, and I MUST have B+ also. it is necessary for pin 3 to have the B+ voltage, but pin 4 must also. If it does not, the tube will not conduct.

In fact, turning off the screen voltages is how Peavey puts all their tube amps in standby mode.

[wbegg]

I'll save Newguy a post. I repaired his amp.

Enzo,

Yes, there was no voltage on the Screen Grid because the screen resistor was open (fried). No screen volty, no conducty!

Pontiacpete,

$25 dollars in my book is a reasonable charge. So many techs charge for "mojo" that is just outright rediculous, like charging $85 for a tube replacement and bias. I charge nothing for diagnoses, and only start charging when the soldering iron switch gets turned on. My equipment is paid for, so why screw the customer? It took me more time to remove the screws from the board than to solder two resistors, hell, I had it fixed before he got home. Should I have charged him more? NO! I couldn't sleep tonight if I did.

Also, "Newguy" is ONE COOL GUY. Enjoyed meeting him.

I am new to this forum, and am looking forward to both learning and contributing. Woooooh.

[Enzo]

Hi, thanks for the update, and welcome to the forum.

[pontiacpete]

I'm glad to see Newguy didn't have to buy a new OT.

Welcome to the forum, this is a great place!

[Newguy]

I'm glad to see Newguy didn't have to buy a new OT.

Welcome to the forum, this is a great place!

You and me both. Money is always tight at my house