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-   -   Rebuilding a Hoffman 610 (http://www.videokarma.org/showthread.php?t=245893)

Eric H 09-10-2009 09:37 PM

Rebuilding a Hoffman 610
 
3 Attachment(s)
I finished up the Motorola 105 was working on so I decided to start on this cute little Hoffman, I think it's a model 610, the chassis is a model 140.

I was able to coax a feeble picture from this set when I first got it several years ago, there was some evidence that it had been serviced up till the 1980's.

It's doesn't work now, even after replacing a lot of the paper caps I get nothing except a little high voltage, probably the filters have died completely by this time, I placed an order for caps with Justradios on Friday right before I left on a trip to N.Y.C. (My birthday present!)

The chassis is stamped with the date of Jun 15 1949.

The early Hoffmans always seem to be a very high quality set, right up there with RCA and Dumont, but then most of the parts seem to be RCA...

jeyurkon 09-10-2009 09:55 PM

That's a nice looking set. Is the stand a matching item for the TV?

John

Eric H 09-10-2009 10:09 PM

Quote:

Originally Posted by jeyurkon (Post 2954050)
That's a nice looking set. Is the stand a matching item for the TV?

John

Thanks John, I don't know if the stand was made for the set, it's not marked Hoffman anywhere (It came with when I bought it) but as you can see it matches perfectly.
Unfortunately the top of the stand is scarred up pretty badly from protruding screw heads and no feet on the TV, it doesn't show though so that's OK.

Charlie 09-11-2009 01:36 AM

That's a pretty set. There was one like it for sale about 4 miles from me a couple of years ago... it was on ebay and seems like the lady want 250 bucks for it. I did not feel very generous that day, so I left it there. The CRT checked on the borderline. I often wonder if she ever got rid of it.

Good luck with it!

Dan Starnes 09-11-2009 02:17 PM

Cool set... And I agree, that table sure looks made for it.

bandersen 09-11-2009 03:01 PM

Yes, that is a pretty set. I like that rounded, glossy cabinet. What do the doors look like ?

Good luck with the restoration!

Bob

zenithfan1 09-11-2009 03:10 PM

Great looking set Eric!

jr_tech 09-16-2009 03:11 PM

Great thread...Thanks! This has helped me to identify my "mystery Hoffman" that has been left un-restored for too many years in my garage. :yes:

Time has not been so kind to my set, however :tears: ... Picture1

It is missing one knob and the Ch selector knob is broken... Picture2

Big "ouch!" on the cabinet...Picture3

Chassis is missing one tube, but seems more or less complete... Picture4

Anybody know what the missing tube behind the tuner might be? ... there was no layout chart or model number on my set (back was missing). Stamps on chassis say
"B013380, Feb 21 1950, Chassis 155"

Good luck with yours, I will be following along for inspiration to begin work on mine.

jr.

Steve K 09-16-2009 05:51 PM

That missing tube is a 6AG5.

Steve

jr_tech 09-16-2009 07:00 PM

Thanks Much! :)

Another question, my set has a 6K6 plugged in just to the right of the 5U4, when I brought the set up slowly on a Variac, it did not light up although it tested ok... I suspect from the pictures in the first post that it should be a another 6SN7 like the one next to it. Is this correct?

jr

Steve K 09-16-2009 07:06 PM

Yes, that is the vertical osc. and output and should be a 6SN7.

Steve

Eric H 09-16-2009 10:51 PM

Hi Jr. Welcome to Videokarma.

I have four Hoffmans total, a couple of them are the same model as yours I think, one is pretty nice, one is a parts set.
I'm not sure what the actual model number is since mine are missing the backs also.

The chassis in the parts set was built Jan 13 1950.

I can probably spare the knob, the cabinet doesn't have any holes in it that I can remember but it's coming unglued and the finish is shot, your welcome to it (the cabinet) if you can pick it up, where are you located?

jr_tech 09-17-2009 12:10 AM

Thanks...I am in Oregon, so I can't exactly swing by and pick it up. Let me get a little more into work on this chassis, if I don't find something really bad (like a blown power transformer or something), I would be really interested in buying some knobs from you. I think I can fix the dented in hole ok, (all the pieces are still there).

Thanks Much!
jr

Eric H 09-23-2009 12:19 AM

1 Attachment(s)
This set is coming along pretty well, replacing all the paper caps really didn't make it work any better than it did when I got it, the picture was shrunk up and folded over at the top.

I replaced the last electrolytics tonight and that did the trick, I left one filter can alone since it's a replacement Sprague and it seems to be fine.

I'm not sure how good this CRT is, emissions are OK but it just doesn't seem all that sharp, I tried another one and it seemed somewhat better.

One thing that made a big difference was plugging it directly in to the wall instead of the Isolation Transformer, the voltage drop on my little 5 amp transformer is significant, I have to remember to remove it if I'm having a problem getting the picture to fill out on a set.

jeyurkon 09-23-2009 12:37 AM

It's starting to look pretty good. You said you only got a little HV when you started. Is it normal now that you replaced the bad electrolytics?

John


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