Yet another High serial 400 rehabilitation......

larryderouin

I'm VERTICAL and Breathing...most of the time.
Subscriber
Had a 400 dropped off for a Restoration, by another AK'er. I normally don't do outside work, but this one intrigued me. Later model 400
SERIAL # 64,746W. Cosmetics (front panel) 8.5 to 9 of 10. Slight streaking of Upper chassis surface.

Owner wants a rebuild to as stock original as I can get it. He understands the upgrades that I do will help it stay in running condition longer and approves. Sooooo.......Gonna do a STOCK rebuild, adding Screen resistors, Cathode resistors, Change Grids to 200K and caps to .1uf. Dave's improved Bal/Bias adjustment but mounted internal (he wants it to look original on top....sorry Dave), all resistors replaced will be vishay or KOA 1% metal film resistors especially to the P.I. so the adjustments hopefully will stay put and accurate.

I asked Hayseed Hamfest to bump up the capacitance to the 1st stage of the Voltage Doubler (Single Cap Can) from 100uf to 220uf to balance the V.D. It's worked well in the one I did last year. Bias P.S. caps will be 4700uf /50V. Will be disconnecting the TAPE/Aux RCA's from each other.

Output coupling caps will be EROFOIL II .1uf 400V and 1000V. These are tested NOS from Apple Scruff and direct from FISHER Plant #2. The rest will be a mix of CD DMT's, DPP, DME's, Wima's, Kemet (X-Y), and K-73's or 42's. I think I can do that with these caps.Will be testing beforeand after each stage for SQ. He wants as close to the original sound as possible, and I share that feeling. So stock it is. I will be testing the current crop of EROFOIL's in it and if they test good, they will stay.

All tubes are FISHER Branded MULLARDS, except for 1 Fisher Branded TELE 12ax7, and one Bogen branded 12AX7. OUTPUT's are FISHER Branded Sylvania or RCA TOP NIPPLE tubes. Lettering is worn off enough I can't tell the EIA Manufacturers code. Yes I tried breathing on it and all it did was sigh......:scratch2:

One of the Mullard 12ax7's broke in transit to the owners house, and another cracked on way here. So to get it up and running (I had one 12ax7 in house), I put all the remaining mullards in the amp, and the Tele as V102. Used a Fisher Branded 12AT7 in V100 and a Known Good RCA Gray plate in V101.

Brought it up on the DBT @100W. no shorts, or smoke. Now for Wall voltage. Started up fine. Been running non stop for a little over 2 hours with temp checks every ten minutes.

Tuning needs a little tweak to align the pointer with the dial. Also pointer wasn't lined up with ZERO mark when turned to full anticlockwise (bottom of scale). This was fixed and dial is closer but still off a little. Low end is about 1/2mHz off, and top end is close to 1mHz off after pointer lined up. Reception on a dipole is very good. Stereo Separation is also very good. The typical cuprits will be addressed here. DeEmphasis (stereo) is off a bit and you can hear it(hiss is almost unbearable in stereo even on strong station). Mono De-Emphasis is good but could be even better. New resistors of the correct value should take care of it.

Gotta go get some batteries for my camera. So Pics will be coming in the next day or two.




Larry
 
"...another AK'er." Hey, that's me!

Larry, Thanks again for taking this job on. I'm looking forward to following this thread as the project moves forward! :)
 
Eastpoint; I would hazard a SWAG and say probably not higher than 79999 if they completed that group. These were probably built in 1967-68 by their serials and at the end of FISHER's tube gear manufacturing time.
 
Here we go again........ There are quite a few threads here with info on the 400-500C-800-C and when they MAY have been built. There are NO RECORDS available from FISHER and a lot of conjecture, overnight brain wracking on their methods, how many production lines were running, did they split the 10000 serial #'s between the lines, etc., not to mention SWAG's to determine when a unit may have been manufactured. Suffice it to say that a 20001-29999 serialed 400 receiver should PROBABLY have been manufactured late in the 1963 or Early 1964 model years. Say May 64 to Feb.65 or so. And that's as close as anyone can get without the production paperwork from FISHER and it's been lost since the 1979 Northridge Calif. Earthquake.
 
It's Tom Nichols. I normally keep private the owners name unless they post and identify their gear.


Well I got the truck running enough to get it down to the parts store to scan it. Ended up needing new plugs. After those it still has a "miss" that feels like an injector isn't doing it's job. $350.00 for a new spyder.:yikes:on a 2002 S-10 4.3L. Guess it'll have to wait for a while. I just spent $300 to do the Intake Manifold Gaskets, all hoses, Thermostat, cap, Intake bolts (one time torque and throw away (this is B.S.!!!!!!).

So taking a break and took some pictures of the 400, beofre and after cleaning with scrubbing bubbles. NEVER have I had the Dial Lamp Sticker loose it's ink! I think I have one on another, if not, I don't think it's a deal breaker. Anyway INSIDE, it's very clean. It does have a Silicon Rectumfrier that the 2nd line has 7117, which IF it's a date code, could have been a replacement but the terminal strip below it is original. I really don't think FISHER Built these into 1971. More like 68 or 69, so this could be a replacement.

There are 4 EROFOIL's in the output stage, and 2 Erofoils in the Toneamp. Everything else is either ceramic(99%) or those damned brown "DOGTURD's".

If the two Erofoils are ok on the Tone amp they'll stay but a few of the ceramics will get replaced. Plus what few 'lytics are in it, and of course the Dogturds.

Everything looks to be in great shape physically.

I cleaned it with "Scrubbing Bubbles", 2" paint brush plus a small 1/4" brush for the hard spots. Wiped down everything with 91% alcohol, and let it sit in the sun and wind for a few hours. I'll reinstall the tubes on Wednesday, after letting it sit under a fan to dry it totally out. Then do some voltages. Fair amounts of Nicotine staining on the faceplate and knobs. Not so much on the chassis.

Looks like I need a new card reader as this one is kaput. I can't upload pictures yet.
I'll try and get a new card reader this week or a USB cable for the camera.
 
Larry, I'm sorry to hear about the truck!

Don't worry too much about the dial lamp sticker. If you've got another sticker... that's great! If you don't... it's not a problem. Did the lettering on the chassis stay intact?

Glad that you are recording the process with some before and after pictures.

I'll let you know when I get the tracking number for the Mouser order.
 
Everything on the chassis is intact. I pulled the 500-C sticker off as it's not pertinent to the 400. Got it stuck away.

I was in the process of tearing it apart when you came up on Sat. Worked all Sat. and Sun pulling the intake, and replacing all gaskets from the intake up. Intake was leaking coolant at the rate of a gallon a week into #5&6 cylinders plus leaking down the back of the block. It's still not right yet, but it runs. Looks like an injection spyder with all the injector nozzles for an 02 4.3L is in the works. Compared to an intake, all hoses, new bolts (I hate yield to torque, single use bolts!!!!!!!) Cooling system clean out of Dexcool and flush and oil change, the injectors are a cake walk!!

Just got back from the local carnival. Took Grandkids. 3 year old grand-daughter hates the teacups, but loves the scrambler! Go Figure. I can't figure out my 66 ear old wife, much less a 3 year old.

No problem on the tracking. It'll probably show up Wed or Thursday.

Lets see if I can finally put up some PICS These are all BEFORE's except for the LAST is an AFTER!!!!.

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There was some serious nicotine staining on the Front cover and knobs. Look closely at the knobs 2&3 pics up. See the Dark staining on the upper surface? All gone now and the front panel is nice and clean, ready for some paste wax. (See Tom? I left you something to do!!)
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AFTER PICS! Damned clouds were in and out and I didn't use a flash.

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Still More Pics..............

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The staining on the end of the Large Cardboard Can cap IS NOT Electrolyte. It's the oily residue from the tar type adhesive used to hold the carboard sleeve to the metal can.
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The last of the Mohicans......for a while....

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And FINALLY....The rectumfrier! This will ge replaced with a heavier duty unit mounted to the side wall permanently. It looks original on the soldering although it's pretty shabby looking joints.
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Well I got the truck running enough to get it down to the parts store to scan it. Ended up needing new plugs. After those it still has a "miss" that feels like an injector isn't doing it's job. $350.00 for a new spyder.:yikes:on a 2002 S-10 4.3L. Guess it'll have to wait for a while. I just spent $300 to do the Intake Manifold Gaskets, all hoses, Thermostat, cap, Intake bolts (one time torque and throw away (this is B.S.!!!!!!).

The spider was bad on my 96 when I got it in 2001. It was replaced and has been dandy since. Mine was dumping gas into the oil when it gave up, so make sure you give the oil a sniff to make sure you aren't wiping out the bottom end. I haven't had to deal with the intake gaskets luckily, but probably because I got rid of the Deathcool about 12 years ago after the water pump went TU on me.
 
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Looks good Larry! Enjoying the pics!

Never considered that the staining at the end of those cardboard can caps was from adhesive... I learned something new.

Do you think some paste wax will remove or minimize the scratching at the top of the faceplate, just above the letter F in Fisher?
 
Tom;

Probably not, it looks to be slightly deeper than the "brushed" finish. I really didn't notice it until you pointed it out and had to look real hard.

Thain; No problem on the oil. I changed it back in May, level hasn't changed, not thinned out. But it WILL be getting changed this week, after I finish running it to clean the sludge remnants. I too got rid of the "Deathcool" 5 yrs ago on both my 02 quad, and 95 Jimmy. Make up a couple of ground wires from the radiator to the chassis. It cuts down on the electrolysis. Dad bought the 95Jimmy new and gave it to me 4 years ago. No problems except the rear hummed all the time from new (pinion gear bearings) and I put a 97 Sonoma rear in it last year. I'm on the S-10crewcab forum so everything that applies for the quad, also applies to the Jimmy. I've seen them dump, and seen them clog. Mine looks to be clogged. So for right now it's a double dose of Seafoam(stuff plain works!) in the tank, then next spring a new Pump and a spyder unit. I maybe drive 50 miles a week in it now, so the seafoam will have plenty of time to clean the crap from the system. But it's beginning to get too expensive. When I started using it about 8 years ago, it was like $5.99 a can, and now $11.99. OUCH! But probably last vehicles I'll ever have. It's a love/hate thing with them. Love them, but hate working on the engine. Imagine having a small block 350 in one!?!!!??!!
 
Mouser order is in. Pending whether the truck cooperates tomorrow, I'l get started on Voltage checks, and taking measurements on the output's as neither of my tube testers does 7868's. From listening to it, I don't anticipate any problems, nor do I feel that there are problems with the 7868's.

I will be putting in Dave's BAL/BIAS adjustment circuit, however it will be internal to the unit. This is how Tom wants it. I'll probably get it all finished this weekend (baring complications) with the exception of the CAN caps probably won't arrive for at least a week or so.

Let me get the rest of the grass cut (taking a break between yards right now) and I'll have to get out the testers, and the scope. And make a run to Radioshack for some breadboard sections and crimp connectors.

Larry
 
Mouser order arrived Thursday. Problems with the truck (which are resolving themselves slowly) precluded any work on it until today.


1.) Installed 100ohm 1/4W screen resistors.

2.) Installed 10ohm 1/4W cathode resistors. Moved resistor to heater ground from pin 3 to chassis ground to prevent unwanted oscillation and hum (see this thread. I do this on all of them so it's nothing new with me..... . http://www.audiokarma.org/forums/showthread.php?t=606802). Thsi also applies to the 500-C and 800-C.

3.) drilled out the bias supply terminal strips (1 terminal) and installed 3 terminal strips to isolate the 200K grid return resistors when I install the improved BAL/BIAS board of Dave's.

4.) Replaced the mpx 1uf/350V cap. Also replaced R222&223 with 15K to bring Stereo De-Empahsis in line.

5.) Replaced .047 dogturds on MPX board (C221&222) with DME's.

6.) Replaced .022uf with K-73 and .01uf with DME on phono board.

7.) Replaced C32

8.) Replaced 47K with 39K (R28) for Mono De_Emphasis.

9.) Replaced C87-88 on Loudness switch. Vishay sprague's.

10.) replaced C77-78 with K-73's.

11.) Replaced C93 thru C96 (ouput couplers)with NOS (I pulled them out of the box @ Apple_Scruff's house) EROFOIL .1uf 400V. Grid return resistors 200K 1/4W. (1/2 way done this is where I quit for the night.

12.) Installed CL-80 inrush limiters, X-Y 1000V "Safety cap", New UF4007's, new.1uf 630v cap for the V.D.

Also replaced the cable clamps that support the wireloom from the front to the back. they were very brittle and one broke just by getting close to it. 1/2" cable clamps from Home Depot took care of it.

As I don't care for splices unless I have no other choice, the only splices are on the one mpx cap (.047uf) and the screen resistors to the wiring. Otherwise I took the joints down to a bare socket lead and started over.

Tomorrow, I build the BAL/BIAS board, and finish up the rest of it, except for the CAN CAPS and related resistors. That will be last.

So on to the pics. Not too many. Get out your drool rag, TOM.

Just started. Screens and cathode resistors in. Note the 220ohm resistor on the last socket on the right (V17) It was connected from Pin 5 to Pin 3. Now Pin 5 to ground. The Large 1.2K 10W (R28) got moved over 1 place as I didn't like the way it hovered over the output transformer wires originally.
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MPX AREA. The 1uf 350V axial is a MUST DO. I was about 1/2 done with this area at the time. In addition to the yellow Illinois cap (C32), the 47K resistor (R28) got changed to 39K to correct the MONO DeEmphasis. The Stereo DeEmphasis is in the hodge podge at the top. The yellowed clamps were also replaced.
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PHONO. Only thing replaced were the .01uf couplers with DME's and the .022's with K73's.
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Ouput section. About 1/2 done and where I stopped for the night. The Right side is finished (as you are looking at it). I installed new terminal strips to support the grid returns individually with either an IBAM or Dave's BAL/BIAS Board. Had to unblot the output transformers to pop rivit the terminal strips in using the original holes. Tom wants the board internal along with the test points so I'll add the crimp lugs to the tube sockets as test points, by forming the ring to fit around the socket lead and soldering it together. The other end is insulated so no problems there. Plenty of depth.
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Different view of the Phono Section.
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MPX Section finished. If you look at the bottom left of the section you'll see one of the 15K resistors(originally 27K), and the wima cap. The opposite's are mounted internally .
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And 3 more pictures,,,,,,NEXT POST!
 

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Last 3 from Today's 8-1/2 hour marathon. My ankles swelled up like my mother in laws used to! DAMN!!!

Anyway, the last 3 pics.


Tone Section. Not totally done here yet. Loudness switch done with Vishay spragues, V10 has K73's, and the 10uf Lytic hiding next to the barrier replaced.
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Power supply started. CL-80's on both legs primary, X-Y cap replaced "death cap(C64), DME for the V.D. cap (C-63). Replaced Diodes with UF4007's.
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My helper disappeared and I found her on the bed, fast asleep. I tell ya this younger generation has no work ethic!! Never finishes anything. I won't complain too loudly, she does keep my side warm, which helps my back.
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I'm gonna soak in a HOT TUB of EPSOM salts, skip dinner, and maybe go to bed.



Larry
 

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