610 Consolette chassis overhaul

[larryderouin]

610 Consolette Chassis Overhaul SERIAL # 11535B

Hx of unit as I know it. It's a running 610 chassis but sounding very tired.
This is the chassis Buglegirl gave me to put in the 510 Consolette. She got it from Audiodon. The original 510 chassis has already been done.

Was getting bored, and this box of parts for the 610 chassis was nagging me to get used, so I went and pulled the chassis out.

Started by changing all the old "dogturds", and the leaking FRAKO electrolytics. Noted about 30 cold solder joints while replacing parts.

The output couplers are supposed to be .022uf, but .03uf's were in it. I checked the values of the resistors surrounding them and they were per the manual, so I yanked the .03's and put in .022uf.600V's.

The speaker screws were stripped so I put a pair of Ratshack 5ways in. I've got Banana plugs so it don't matter that they are right up against each other.

Ran out of Terminal strips and 47uf/450V caps. Order is in for those. I have enough 27uf 450's to do the isolated CAN CAP, But have to get new a isolation pad for the can. Gonna stuff that one. May stuff the 4 way if the caps will fit other-wise I'll go with Terminal strips and offboard caps.

The MPX addition is a little weird in the setup. Section 4 of the Rotary switch is probably different on the CE-III than the 610. On the 610 the wiring for the FM section has pin 9 and 8 on the back tied together with Pin 9 Front tied together with them. Pin 9 on the front has only R36 to ground on it.

On the CE III Pin 8 is used for the FM OUTPUT, and is tied to PIN 9 Front? But on the 610 switch that puts the back of 9 in circuit too. So I Moved the R36 from Pin 9 to Pin 8 on the front to keep the circuit as the schematic. (HOPEFULLY!!)

FM OUTPUT was connected to Pin 8 Rear Section 4 Selector Switch

MPX OUTPUT was connected to the Junction of C47 and R32-R35.

MPX INPUT was connected to PIN 9 Rear Section 4 Selector Switch.

If the MPX works on it fine, If it doesn't I can reverse everything in about 10 minutes.

It'll be a couple weeks before I get to finish it up with mouser order, and getting ready for the workweekend on the sub this coming
weekend and the inevitable re-couperation from trying to do a years worth of work in a weekend. As I get parts and do some more, I'll add to it.

The pics include the original 610 schematic of the area and the CE-III schematic of the same. No changes to any caps
or resistors need to be made.

610 schematic of the area for MPX

CE-III of the Same Area

Da Whole Enchilada...

Close up of MPX Jacks and wiring from Left

Close up of MPX Jacks and wiring from right

Back end with OUTPUT Tubes and 5way speaker jacks

Top of chassis showing location of RCA's for MPX.

Junk Parts. Every on of these caps are leaking according to my cap tester.

FUN, FUN, FUN!

Going to bed!

Larry

 

[IMTubeHead]

Burning the midnight oil, eh Larry? I feel really lazy now sitting here reading about all of your hard work here. I'll get over it...anyway, your stuff is MUCH MORE interesting than my stuff!

John

 

[larryderouin]

I was up again @ 3:00 and again @ 5:00 roll over and back to sleep. Yeah right! finally got up @ 8:00. Full day of running around (chicken with head off!)


Larry

 

[apple_scruff]

Your on a roll! How many 47uf do you need? If 400VDC will work let me know I just bought about a 50 of them. I will send you a few.

 

[walyfd]

I get spurts like that, too. I can remember not being able to sleep thinking about a carburetor I was working on. Got up in the middle of the night and started boiling it on the stove.

Wish I had your audio talent, Larry!

 

[Andyman]

Are you using that in the console?
I recently had one, but the 2.5 ohm output was a concern for use outside of the console.
The iron good looks sweet on these, but I don't know how to tweak it.

Nice work, btw.

 

[larryderouin]

Thanks guys.

Andyman; Yes it's used in the console which is actually a 510. So i have both chassis' for it. No problems with it and the 2.5ohm output.
Guess it may be possible to swap out a transformer from a later el-84 amp like the 480A or 481A or even a 30A. With the 3 speakers in parallel it evens out anyway on it. So probably better to leave it be.

Apple: the cans are 40/40/40/20 @ 450/350/350/300 and 20/20/20 @ 350/350/350
I've got all the 20's and 1 40. I'm concerned about the size of the 40 I do have (see whole enchilada pic....those two are temporary mounted to see what kind of wiring I'd have to run.) and ordered already 3 Nichicon 47/450 pencil size caps. With the 20's being that same size it shouldn't be a problem now. thanks for the offer.

Walyfd; I actually took a break last night. Had to get a new bed and put it together, so didn't have a chance to work on it last night (nothing left to do except the can's).


Larry

 

[Omegaman]

Familiar territory for me as I am enjoying the fruits of my own 610 restoration. I use mine about two hours a day, listening to at least one LP.

That FM MPX modification is cool. Thanks for explaining the FM out and the MPX mod

Great job Larry!

 

[larryderouin]

Thanks Omegaman for picking that up. Indeed it was. No longer tho. I took the picture before i soldered that connection in.

 

[audiodon]

It's good to see this amp again.

The console had a lot of veneer damage where the glue of the veneer had lifted from the underlayment. It was a high mileage unit, but had been stored in a damp unheated space for quite a long time . . . long enough to really do a job on the speaker cover fabric . . . plus it had the extra benefit of holding varmint nests.

I saved the solid wood trim. My plan is to wrap my pair of 30A amps in Fisher console trim. In one place, the "The Fisher" gold lettered logo will show.

 

[larryderouin]

When I got it from Fran, I brought it up on a variac and it worked fine considering it's age and original caps. Tuner is actually the best part of the unit. It pulls in pretty much everything around with just the "T" dipole on the back and the ferrite for AM. This is one of the few Fishers I have that doesn't need an external antenna where I live. Usually Annapolis is terrible for reception but the 610 does really well. But it was tired, and it showed in the increasing distortion with volume increase. Tubes are good, so I started on the caps. All of the FRAKO's were physically leaky. And only 2 of the "dogturds" did not show leaky. But their values were all off by at least 50%.

Once I get the new caps for the can's I'll stuff them and install. Then I'll compare it with the 510 (phono only) for the phono section only. Should be very close if not identical.

Larry

 

[larryderouin]

Got the can cap replacements. Installed and fired it up. Other than dirty pots and tuning cap (noisy), it's good. And the MPX mod works. Now to clean the pots and the tuning cap, and put it back in the cabinet.

Larry

 

[apple_scruff]

Good deal! Let us know how it sounds. After this whats your next project?

 

[larryderouin]

Probably finish up the cabinets on my SX-790 and Sx-939 with some Parts Express vinyl sheet. Then come spring, after a few weeks of cutting grass, new veneer on the 510/610 and 560 cabinets and finish up the Coronet cabinet.

 

[larryderouin]

I put it in the cabinet and fired it up. A SQ is a lot more defined than as originally received. It seems that the speakers are the weak link here (or the 2.5ohm transformer). High's are rolled off above 12K on the factory speakers (8" with whizzer full range). With a Sonotone cart, there is a lot of background noise picked up by the cart. I may try a Pickering 400V.3 with a outboard preamp. However the AM and FM is very good. Probably the best reception short of the TA-600.

The 510 chassis was then installed. I hear no discernable difference between it and the 610 chassis in Phono. Again the speakers are the weak link here. I did connect a pair of KLH-20's and the SQ went WAY UP. High's were more lifelike, but still somewhat muted.


Larry

 

[larryderouin]

Forgot to add that the standard 5-way's won't work on the 510/610 chassis as they are too long when installing the chassis into the console. I had an original type connector board on a donor chassis (175-T) so installed that instead. The one's that Audiodon uses that screw into the old screw mount will work. I just have to find the part #'s and order a pair. Until then the screw mounts work fine.