Well, ive been working on the h251. I replaced all of the electrolytic and paper caps and the bad rectifier tubes with new EH 5u4gb's. The set still shows few signs of life other than lit filaments and a low hum from the speaker. What section should i attack next??

I would check all voltages coming from the power supply...there may be open resistors leading to some stages not receiving DC voltage.

Im kinda new to this, i've been working on vintage radios for awhile, and never replaced the molded mica caps. Should i replace them here, as Tv circuits are more sensitive to out of spec caps? Also, Are the micamold caps paper or mica?

Mica caps are usually quite reliable, although I have had to replace a few in old TVs and boatanchor radios. I generally don't replace one unless I have first tested it, or have a strong indication that it's faulty.

Micamold caps are paper caps in flat, usually rectangular cases, and should be replaced. Some have colored dots, others have the values stamped in the case, something I don't remember ever seeing on a mica cap. I replace all of these without wasting time to test.

This article has a couple of photos and some guidance on how to tell one from the other.

http://www.antiqueradio.org/recap.htm

Note that the capacitor's value is a tipoff. Micas have very small values. Micamolds have larger values, much the same range as paper caps.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Have you hooked an antenna or DVD player to it yet to check for sound?
Sometimes a set won't make any noise till you get a signal through it, does it make any crackling noise when you change channels, this would at least indicate your audio is working.

Can you tell if theres any high voltage? you can hold the blade of an insulated screwdriver near the top of the IB3 HV rectifier tube (or whatever number it is) and see if you can draw a small arc, do not ground the screwdriver for this test and keep one hand in your pocket to avoid electrocution!!

Concentrate on the power supply first. Check the rectifier tube(s) for DC output. If none, check the transformer for secondary voltage (AC). If you do have sufficient DC output from the rectifier tube(s) then trace the voltage through each dropping resistor as the power supply branches out to the various stages. Most likely, one of the power resistors is open.

What I really need now is a schematic. I've been trying to do this blind untill now. I guess its time to go look for one. If anyone has one, let me know.

check your damper tube and fuse. ive been there before. you get sound, no pix.

Is there a chassis number on your set? I have some original Westinghouse service info but couldn't find any that included your model number. However, checking in Sams shows your model associated with some other models that I do have factory service info on. Either way I should be able to get a schematic scanned and emailed to you.

I'd hold off on any more power-on testing until you have a schematic. Otherwise, if the flyback goes, you'll have the most expensive potted-plant-stand in town! If someone locally is soaking you big bucks for EH tubes, you may be in a town big enough to have a library. Go to the main branch and ask the reference/periodicals or technology desk if they have Sams' Photofacts. They usually keep them out of sight, but the index is at their fingertips. Your TV should be in there. You could also Google Sams' and plug-in your model# into Sams' online-search page.

I'd look for a glowing plate on any tube, especially the horizontal output, damper and those new 5U4's. In fact, I'd put the old ones back in until you have this all sorted out. Some of us old farts are rightly suspicious of fleece-the-musician re-branded Chinese/Soviet Bloc tubes like EH (I do own one of their fuzzboxes, however, with no tubes). You'd be better off finding some sturdy old JAN surplus 5U4 or 5R4's on ePay and give them a good home!

I'd hold off on any more power-on testing until you have a schematic. Otherwise, if the flyback goes, you'll have the most expensive potted-plant-stand in town! If someone locally is soaking you big bucks for EH tubes, you may be in a town big enough to have a library. Go to the main branch and ask the reference/periodicals or technology desk if they have Sams' Photofacts. They usually keep them out of sight, but the index is at their fingertips. Your TV should be in there. You could also Google Sams' and plug-in your model# into Sams' online-search page.

I'd look for a glowing plate on any tube, especially the horizontal output, damper and those new 5U4's. In fact, I'd put the old ones back in until you have this all sorted out. Some of us old farts are rightly suspicious of fleece-the-musician re-branded Chinese/Soviet Bloc tubes like EH (I do own one of their fuzzboxes, however, with no tubes). You'd be better off finding some sturdy old JAN surplus 5U4 or 5R4's on ePay and give them a good home!

I had the 5u4EH's laying around from an amplifier i no longer own. I already inquired with my library about photofacts, the first time the librarian said they had them but no longer allowed people to access them. This was two years ago. I went in about two weeks ago and asked again. They now tell me they threw them out because they were tired of looking for someone to take them, all three filing cabinets full. Lets just say I wasn't pleased.

Also, where would the fuse be located on the chassis? There is something that looks like a fuse holder, made of black bakelite, but it is much to small to hold any standad fuse type. I figured it was just a test point.

Sorry to hear about the library. Usually it's a place where (seemingly) enlightened people work :boring: Hope the rest of your local agencies have a little more spring in their step!

I had an energetic young lady find me a Sams at the library in Bellevue (3 miles from Microsoft) once; she went to the back THREE times to look, only to finally come back, saddened. She says "I just don't see your McIntosh MR-55 on any of these folders". Since this is geek country, she thought I meant APPLE MACintosh. I explained to her it was HI-FI gear, take a look in the TV folders, and she went back one more time and found it! We had a nice chat, and I thanked her for her hard work. Seems that even in the wealthiest Zip code in a ten-state area, not everyone has seen a McIntosh!

Any chance you could post a photo of the black part? I'm really curious myself, and if I don't know, my ex-shop-owner friend or someone on here will. I had a 24" Westinghouse with an all-copper chassis back in '67. It had a very sensitive tuner, and when the AFTRA strike had all the Seattle stations off the air that summer, I was DXing all the Portland stations with it!

The chassis number is;

D 007181