Questions about a Fisher Console restoration

[PJP122954]

Just purchased 49A & 49T and Dual 1010 TT from Electra Console and 680T from Ambassador. Im planning to place in my Futura Cabinet. This will be a real hybrid once it is complete. It needs a good cleaning, testing and most likely recapped. I have absolutely zero experience working on
electronics except for hooking them up. Question is....can I do this myself or should I have a professional look at it. Really don't want to spend a bunch of money for something I could do myself with some patience and instruction. Are there any good books or YouTube sites that can assist me. I can post closeups of components if anyone has a desire to point me in the right direction. Not sure where to start or what the first step should be. Thanks all!

 

[grindfix]

Check this thread where I did my 49A/T chassis
http://audiokarma.org/forums/index....-console-this-weekend-worth-repairing.847812/

 

[larryderouin]

Plus I did a few 49A/49T rehabs' so the experience base is there. The 49T might be an easier start for you as there isn't much to replace internally. 6-7 individual caps and the can, unless you do the phono circuit too.

 

[grindfix]

I would start with building DBT (dim bulb tester) and see if it will produce sound. If it stays stable and no noise - run from the outlet directly and take DC offset and bias reading (very carefully!)
Schematics and service manuals can be found at fisherconsoles.com

Edit:
Use mini alligator clips for testing. One slip will take out those hard to find Germanium output transistors.
If you have Harbor Freight store near you sells a test kit
https://www.harborfreight.com/18-inch-low-voltage-multi-colored-test-leads-66717.html

 

[larryderouin]

BIAS isn't going to be adjustable. It's had the FACTORY MOD done. Just take voltage readings. Make a copy of the schematics and write the voltages on the schematic in RED PEN, next to the "IDEAL" voltages. Without the benefit of a variac all voltages WILL be slightly high. If consistently higher, and below 10% above IDEAL you'll be ok.

 

[PJP122954]

I would start with building DBT (dim bulb tester) and see if it will produce sound. If it stays stable and no noise - run from the outlet directly and take DC offset and bias reading (very carefully!)
Schematics and service manuals can be found at fisherconsoles.com

Edit:
Use mini alligator clips for testing. One slip will take out those hard to find Germanium output transistors.
If you have Harbor Freight store near you sells a test kit
https://www.harborfreight.com/18-inch-low-voltage-multi-colored-test-leads-66717.html

Thanks.....I'll head to Harbor Freight. They have everything...

 

[PJP122954]

Plus I did a few 49A/49T rehabs' so the experience base is there. The 49T might be an easier start for you as there isn't much to replace internally. 6-7 individual caps and the can, unless you do the phono circuit too.

 

[PJP122954]

Larry.....you seem to be the best source on this site. Can you do your magic and circle the caps etc that would need to be replaced. Thanks

 

[larryderouin]

Gimme a day or so and I'll pull up an overlay one of the other guys did for the 49A with regard to the caps and resistors. Basically you're gonna replace all cardboard covered electrolytics, under and on top (the ones on top are CAN CAPS and can be replaced with underneath caps ) Most of the Dark brown (kidney bean shaped) Dog turd caps, the mustard and seafoam green caps. The 330ohm 3w resistors at the top get replaced with 5W units, and the Orange resistor in the middle gets replaced with a 10W unit. This is right off the top of my head. The Diodes in the power supply can be replaced with a 4A Bridge rectifier.

 

[larryderouin]

Some links for you to peruse while I find the overlay.
https://audiokarma.org/forums/index...=post&o=date&g=1&c[node]=172&c[user][0]=42316
https://audiokarma.org/forums/index...weekend-worth-repairing.847812/#post-12223318 Post #18 in previous link (Read the whole thread.)
https://audiokarma.org/forums/index.php?threads/diplomat-49a-49t-noise-question.627730/
https://audiokarma.org/forums/index.php?threads/diplomat-49a-49t-noise-question.627730/#post-8313065 Post #4 from previous link.

 

[grindfix]

Here are before and after pictures of mine. I did not re-stuff can caps and mounted replacements under the chassis. I like the way it turned out. You need to make sure that pair of bias caps and pair of voltage doubler caps have no contact with the chassis.
Bias pots are not removed but are disconnected

 

[PJP122954]

Thanks Larry.....I do appreciate your help.

 

[PJP122954]

Here are before and after pictures of mine. I did not re-stuff can caps and mounted replacements under the chassis. I like the way it turned out. You need to make sure that pair of bias caps and pair of voltage doubler caps have no contact with the chassis.
Bias pots are not removed but are disconnected

Here are before and after pictures of mine. I did not re-stuff can caps and mounted replacements under the chassis. I like the way it turned out. You need to make sure that pair of bias caps and pair of voltage doubler caps have no contact with the chassis.
Bias pots are not removed but are disconnected

Thanks......your photos help....I do best with visual comparisons.

 

[PJP122954]

Gimme a day or so and I'll pull up an overlay one of the other guys did for the 49A with regard to the caps and resistors. Basically you're gonna replace all cardboard covered electrolytics, under and on top (the ones on top are CAN CAPS and can be replaced with underneath caps ) Most of the Dark brown (kidney bean shaped) Dog turd caps, the mustard and seafoam green caps. The 330ohm 3w resistors at the top get replaced with 5W units, and the Orange resistor in the middle gets replaced with a 10W unit. This is right off the top of my head. The Diodes in the power supply can be replaced with a 4A Bridge rectifier.

Gimme a day or so and I'll pull up an overlay one of the other guys did for the 49A with regard to the caps and resistors. Basically you're gonna replace all cardboard covered electrolytics, under and on top (the ones on top are CAN CAPS and can be replaced with underneath caps ) Most of the Dark brown (kidney bean shaped) Dog turd caps, the mustard and seafoam green caps. The 330ohm 3w resistors at the top get replaced with 5W units, and the Orange resistor in the middle gets replaced with a 10W unit. This is right off the top of my head. The Diodes in the power supply can be replaced with a 4A Bridge rectifier.

Hey Larry.....sorry to be a pest but did you ever find your overlays for the 49A/49T restoration? Thanks Pete

 

[larryderouin]

Been busier than a 1 armed paper hanger. I'll get the Desktop lit off and see if I can find them.

 

[larryderouin]

I found the files. They are actually for a 59A from a 65 Ambassador. NO PROBLEM. The 59A adds 4 transistors to the total for 8, vs. 4 on the 49A. Parts are generally the same value and voltage. Parts are in the same location. Parts that are on the overlay, but not on your 49A (Mainly on and surrounding the outer transistors in both rows) disregard. 1st is the capacitor overlay, 2nd overall resistor overlay, 3rd is closeup of the output transistor section.

 

[grindfix]

Wow! This would take me forever to do. I'm behind on computer usage for stuff like this.
I had no issues identifying components based on schematic and parts list from the service manual, but those images would definitely speed up the process. I think, both chassis took me about 6hrs total. Most all power supply capacitors I used were Nichicon UPW series. If carefully planned, all capacitors are possible to place under the chassis and not to mess with stuffing the cans. 49T preamp/tuner chassis is another story. There is no room for can caps under chassis. Possible, but not going to look nice.

Larry, did any of your amps have sheet of metal under the chassis? My amp was bolted directly to the back of the left speaker board. Thinking about adding sheet under it. I have noticed a faint hum with no signal input.

 

[larryderouin]

These aren't mine. They were done by an AK'er about 4 years ago for a '65 Ambassador. The '65 Futura also uses the 59A.

None of the 49A/59A amps have a bottom cover. They were mounted directly to the wood cabinet. You can glue some aluminum foil to the cabinet slightly larger than the amp itself. Use heavy duty as the standard is too thin and fragile. And make sure it's flat against the wood. You might also increase the capacitance of the 4 section cap in the amp, and/or in the 49T. All of mine have a slight hum with no input. Try shorting plugs in the AUX, Tape monitor, if not being used.

 

[PJP122954]

I found the files. They are actually for a 59A from a 65 Ambassador. NO PROBLEM. The 59A adds 4 transistors to the total for 8, vs. 4 on the 49A. Parts are generally the same value and voltage. Parts are in the same location. Parts that are on the overlay, but not on your 49A (Mainly on and surrounding the outer transistors in both rows) disregard. 1st is the capacitor overlay, 2nd overall resistor overlay, 3rd is closeup of the output transistor section.
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Wow and thanks. Best place to purchase parts? Mouser?

 

[grindfix]

Digikey Is another option. They seem to deliver quicker but I guess it depends where you are. I’m in Ohio and typically they deliver two days quicker than Mouser. Another thing, I had a lot of order errors from Mauser lately.