Recent content by nmwhitneyjr

My apologies for bumping this old thread, but it deserves the attention of anyone researching mods for an 800c/500c.

POINT OF CLARIFICATION regarding the screen stability mod: Where does the supply line (orange wire on my 800c) connect? In the original configuration it connected at pin 8 of V10. I moved the orange supply wire to pin 1 for the mod. But I moved it back based on this article...

Grid stability resistor mod now in place. Started 'er up with the Tung Sols. Set all of them to .34 (they were surprisingly easy to do). Then using the probes on each pair, v10/v11 were at .001 relative to each other. V12/v13 were .002 relative to each other. I let her warm up for 20...

Assembled an IBAM yesterday. Installed it today. Here are the readings: V10 3 = 446 4 = 411 5 = .345 6 = -16.7 V11 3 = 446 4 = 411 5 = .347 6 = -17.84 V13 3 = 445 4 = 410 5 = .347 6 = -18.1 V14 3 = 446 4 = 410 5 = .347 6 = -18.68 Now only 18v higher than target value on the plate (and...

-25.6 off the rectumfier. Is the screen stability mod desirable (IBAM installation notwithstanding)?

Is that the same as the voltage off the neg tap of the rectifier?

Also, if I replaced the coupling caps with Russkie K40Y-9s, should I get .1uf or .047uf in conjunction with the IBAM circuit?

Testing Round 3: Wall voltage - 121.5 R119 now a 5.6k ohm resistor v10 3 = 458 4 = 424 5 = .162 6 = -21.01 8 = 424 v11 3 = 458 4 = 425 5 = .210 6 = -21.00 8 = 425 v13 3 = 458 4 = 425 5 = .241 6 = -21.01 8 = 424 v14 3 = 457 4 = 424 5 = .253 6 = -21.03 8 = 424 Not as much of a difference as...

I’ll swap the 5.6k in tonight and post readings.

I have 3 dream cars: At the obtainable end of the spectrum: Any DMC12 has to be unmolested though. Too many have gotten the BTTF treatment. I would, however, insist on an OUTTATIME vanity tag. Jensen Interceptor. The "Bad Girl" from "Luther" (the BBC cop show w/Idris Elba) drove one...

Had a mid-life crisis and did the only thing an irresponsible man could do:

Serial#: 42752 M C16 and C18 were replaced with .047uf 600v. C17 and C19 replaced with .047uf 400v (provided in the Metalbone kit). I don't have any pots about. DigiKey order will be here this week. But the Metalbone kit supplied several resistor options for R119. I put in a 2.7k, but I...

Powered my 800c up and let it sit for 20min. Per my kil-a-watt meter: wall voltage = 120.4 800c was drawing 1.1 amps 800c was drawing 118 watts Tube Pins: v10 3 = 456 4 = 423 5 = .112 6 = -22.35 8 = 423 v11 3 = 455 4 = 422 5 = .143 6 = -22.31 8 = 423 v13 3 = 455 4 = 424 5 = .173 6 = -22.37...

They are branded RCA so I'm assuming they are replacements... but they look older than I feel. I've ordered a set of Tung Sol's from a local dealer that should arrive this week. Any tests I can run with my fluke dmm to determine if the tubes are tired?

Round 1 - after 15 minute warm up v10 Plate: 458 Cath: .12 v11 Plate: 458 Cath: .16 v13 Plate: 458 Cath: .18 v14 Plate: 458 Cath: .19 So not optimal. Based on the heat damage to the cabinet, I'm assuming that these tubes got rode hard and put up wet... not sure that's the cause here...