Rca 8-t-241

[DaveWM]

this is a set with no cabinet (termites). the plan is to just clean it up and maybe mount on a nice base with some rubber feet, put it out for demo to show off the tubes. My only issue is it came from a set that had the CRT mounted to the cabinet, so I need to figure out a way to make up a mount that I can affix to the chassis. I also like the idea of an exposed chassis that lets me do a CRT test with a working chassis, since B&W tubes often look fine even though they test weak. I posted a bunch more over on ARF about how I got this far, but figured I would post the end result to share with those that are primary VK folks.

[mstaton]

Nice picture on thaty set.

[DaveWM]

this was an experiment in TV repair vs restoration. I went over it in some detail over there, but to summarize I wanted to see how little I could do to get a set up and running. By little I mean part replacement as I know its common practice to shot gun all caps. On this set I ended up leaving all the orig can caps (One had been replaced at some time in the past maybe two) all resistors were left alone, most of the film caps had to be replaced (wax and bumble bee, they just tested way too leaky for me to even consider). And two really bad tubes (hv rec with no emission and a shorted tube somewhere else).

I did take the time to reform each section of the cans, out of circuit, but thats it. The only real problem was an incorrect horz osc coil that kept the HV from wokring. I dont know what the deal was as the set came from an old tv shop so maybe someone was trying to fix it and did not have the correct coil, and tried to make it work (had a miller 6194 needed a 6183).

after getting the HV back the vert would not sync up and had very bad fold over. That was fixed with some spray on the vert hold pot, did not expect it to be that easy as the pot seemed to be working as far as having some effect.

What I really wanted was to get it to a min operating state and then try my diagnostic skills out on fixing it (like using the 1076 to trouble shoot the HV). So leaving in a few faults was ok.

I plan to fuse the B+ and see how well the reformed can caps hold up. will run it a bit everyday rather than letting it sit for 6 months then slamming the B+ back into it.

[DaveWM]

I did leave in all the mica caps, including the ones in the sweep circuits. I have had issues in the past with those, but again, the idea being to leave them alone and maybe have to trouble shoot a cap. that way I can see the problem and, hopefully, use some logic and trouble shooting skill to see if I can zero in on the problem. So far so good on sync and sweep, almost hope a problem will develop just so I can find it. The one kind of problem I did NOT want to trouble shoot is a short circuit or cap polarity issue due to my shotgunning of parts.

[David Roper]

It is an excellent chassis. In my (admittedly limited) experience it is a much better chassis than a Du Mont 103: easier to get working and a better performer overall.

[Sandy G]

You could always "Spiff" the chassis up a bit, spray-paint it grey, & just leave it/use it as is...I have a Scott 800-B chassis-no TV-but I have no real desire to ever try to get a cab for it, the chrome is SO pretty w/all the Firebottles a-glowin'...

[DaveWM]

its not to pretty, some small rust spots, prob a 7 on a scale of 1 to 10.

I was thinking of doing some experiments with ways to clean it, as I do plan to have it out in the open, mostly as a conversation piece (ha ha isn't that what the fish tankers say). I did leave on film cap in, a .05 black beauty near the damper tube, and a "tone" cap off the loudness tap, the true audiofools should like that.

[DaveWM]

if anyone has any pics of the chassis CRT mount hardware please post a pic, could use some help on how to best do that part.

[DaveWM]

I just realized my T-120 mount hardware should be close to what I need so hopefully I can copy it to use to mount the 10BP4

[DaveWM]

hmmm interesting the HV sags quite a bit (down to 6kv from 8kv) with max beam current in CRT. Think I subbed the HOT no change, next will be the damper. The HV rectifier is NOS. I wonder if its possible the resistor in the filament circuit could be high dropping the emission of the 1B3?

Looks like I got my wish some problems to trouble shoot

for starters I think I will get my 1076 out and do the plate drive thing and see if it still blooms, that should isolate the problem some what.

[DaveWM]

corona discharge sound coming when HV down, not sure what happened but I think it may have been coming from around the HV anode. I was moving the chassis to try and get a better look and it stopped and the HV popped back up.

Time to call it quits for tonight

[Boobtubeman]

Heres how the 10BP4 mounts on my RCA...

Steve

[ChrisW6ATV]

Originally Posted by DaveWM

if anyone has any pics of the chassis CRT mount hardware please post a pic, could use some help on how to best do that part.

Dave-

I removed and reinstalled the CRT in my 8-T-241 a while back but I did not take any pictures. It is comparable to how a 630TS or 8TS30 holds its CRT; the center part of the front panel with the screen/mask unbolts from the rest of the front panel, which has a round hole larger than the CRT's diameter and some adjustable metal clips with rubber bumpers to hold the CRT's front rim centered.

If Steve (Boobtubeman) built his mount for the chassis in his picture, that could give you ideas of what to make for yours. You need something that bolts onto or under the chassis and then supports the underside of the CRT, with a strap or other item around the top. Be careful!

[snelson903]

Originally Posted by Boobtubeman

Heres how the 10BP4 mounts on my RCA...

Steve

ha i got the same chassis on one of my side benches its out of 49-50 rca victor use's the 12Lp4 TUBE its been a project i pick around on every once in awhile, its been all recaped and i restuffed the large can caps on # c4 one of replaced caps after stuffing is a 10 mfd 450v on mine it runs hot every other cap is nice and cool on the chassis .its connected with vert output trans and yoke i thought it just might be a cheap miec cap tried another samething i clipped in a 20mfd 450v its ok runs normial , i checked the resistance of the yoke and vert output trans, the output trans shows lower than it should ,i havent realy devoted alot of checkout time with this chassis just wondering have you had any similer problem with yours. i probley should try a different manufacture of caps a 10mfd 450 before i do anything more just in case i have a problem with the lot 10mfd i have ,mybe there realy 250v and there marked 450v.

[DaveWM]

Thanks for the pics guys. Had not noticed the hot running caps, but good to know. If you have one a cap tester that can test for leakage at rated voltage and power factor or ESR may be a way to look into those caps. I always check the new caps that go into sets, I do not really trust a lot of the stuff that comes out of China, I sometimes wonder about the quality control, but since they seem to be the sole source for most everything you have to buy and check. Its one of the reasons I do not rush right out and replace all the cans anymore. I have found that often the existing cans work fine. Prob 1/2 or more of my mid 60's sets have the orig Mallory cans and work fine. I DO recommend fusing the B+ right before the 1st doubler or filter, regardless of new or old caps. Its seems logical since that (Ecaps) is the only place where there is a chemical product in the set.

I am going to have to study this for a while (the CRT mount) I def want it attached to the chassis so I can flip it on its side and be able to work on it.