New proect! 1953 Hoffman Television Super Receiver Mark V Tv Phono Radio Console
 

Just got off the phone with the owner.

its a 1953 Hoffman Television Super Receiver Mark V Tv Phono Radio Console.
like seen here. https://i.imgur.com/0qY8THZ.jpg


don't have it in my paws YET
but as soon as i get my tax refund, it's about 20 mikes from here waiting for me! :banana: :D

In the meantime, I will start putting up what pics I have of it.

I did spot something a bit odd in one pic, but at this point, I don't know what type of CRT it has, or if I'm seeing it right.
I just know that it seems to have a 19-21 inch rectangle shaped tube.
The odd thing is, in the picture with the back off, I did not see any ion trap.
Perhaps it just could not be seen in the shot, or the tube does not need one? Who knows?

Won't know for sure till I get it in my hands and can look stuff up on it. :O

https://i.imgur.com/3NRs046.jpg
https://i.imgur.com/AvbRiSV.jpg
https://i.imgur.com/xKcQP02.jpg
https://i.imgur.com/fPBWb2m.jpg
https://i.imgur.com/8quCK1V.jpg
https://i.imgur.com/sKnsm1N.jpg
https://i.imgur.com/jfU9zBW.jpg
https://i.imgur.com/AOTYFjc.jpg
https://i.imgur.com/Qkwc1S9.jpg

Sams says its a 21FP4 and needs a ion trap.

but I dont see one in the picture :O

So it's A: missing a single ion trap for a 21FP4 and I will somehow have to find one, NOT EASY! T_T or B: it was rebuilt like the one I got from dieseljeep last year, and has a inline gun assembly and no longer needs a trap, I will have to get a very close look once I get it in hand to know for sure. :O

Talk about ironic, finding ANOTHER set with the same type tube!

I think I have a spare single ion trap in my junk boxes....If you end up needing one remind me to check.

This is a bit nit-picking but the term "inline" when speaking about CRTs usually refers to the more modern type of color CRT where the three guns sit side-by-side instead of in a delta pattern.
I think a better term would be "straight" gun as opposed to "bent" gun.

It could have a rebuilt "aluminized" tube, which needs no ion trap.

I will know once i get it in my hands :P

been looking at the sams and did see something odd.

https://i.imgur.com/adVNqf1.jpg

color converter plug?
on a 21 inch set? I wonder if they really ever made one.


and it seems that this chassis had huge sandbar resistors (3) that have a reputation of disintegrating, or so has been shown on the sets that shango066 has had shown before, and they all seem to have the same types of power systems, I'm pretty sure i will have to rebuild the voltage divider. no biggie

I should be picking up the set sometime this Sat, and once I get it home one of the first things I will do after removing the deadly asbestos from it is looking at the CRT and putting it on my B&K tester to see how good it is and try to work out no ion trap can be seen in the picture.
Also take a good close look at the FBT, remove the 5U4GB bring the heaters up slow and see if there is a good 750+ ac at the 5U4GB plates.

If you need a manual for this TV, I have the hard copy of the Sam's for this TV in my Sam's Collection that I can scan and send your way for you.

And, yes I did check to make sure it was the same unit as yours, so I didn't accidentally make the mistake I did with the guy on here that is working on the old Silvertone TV, and think I had the manual for his TV and turned out to be for another similar TV.

Houston, we have a 21FP4D !
https://i.imgur.com/5eCXbmn.jpg
It was obviously solaced at one time.

and it's good!
https://i.imgur.com/czxSDyE.jpg

the FBT looks ugly but the resistance test looks OK
https://i.imgur.com/YZwTVMG.jpg

https://i.imgur.com/KKSgXFJ.jpg
https://i.imgur.com/66zzV80.jpg
https://i.imgur.com/wezeaer.jpg
https://i.imgur.com/ltHIVeP.jpg
https://i.imgur.com/oQpJZgJ.jpg
https://i.imgur.com/N4jmIbB.jpg

I dont think that motor was meant to be sitting on top of that sheet of asbestos asbestos like that :o

chassis out
https://i.imgur.com/aK2QgZX.jpg

https://i.imgur.com/N3Aigae.jpg
dirty tuner

https://i.imgur.com/rhFxhT1.jpg
https://i.imgur.com/4fu5OTH.jpg

lots of paper caps

https://i.imgur.com/iRw0MwE.jpg
https://i.imgur.com/4lMsaHY.jpg
as expected, sandbars are VERY bad.

https://i.imgur.com/a2j1pCY.jpg
radio chassis

I have the SAMs for the TV but not the Radio,
have to find that somehow. :(

I HAVE THE POWER!!!!! :D

https://i.imgur.com/mtsjjJd.jpg
https://i.imgur.com/NZGPLNF.jpg

Now its time to get parts.

As expected, EVERY resistor in the voltage divider tree is bad, some VERY bad, even the Candohm

all the sandbars are toast.

75 ohm is testing as 560k :o

just ordered a mess of parts

does it have the part for the Radio section? I'm still missing that part T_T

Sadly, the power transformer in the radio section is very VERY dead...

https://i.imgur.com/sS6609i.jpg
https://i.imgur.com/mznGDhX.jpg

Which makes finding service info for it all the more important. :sigh:

Is there a chassis number for the radio in the set, or a 'see this folder for radio' note in Sam's?
If not you could search radio consoles by that brand on the radio museum website and look for a radio with a similar face and tube compliment.
If the radio and TV don't share power supplies/audio output stages then it's almost a guarante that there was a radio (or radio/phono) only version sold.

Can't seem to find it on RM :(

11 tubes
5U4GT
6V6G2 X2
6BA6 X3
6SN7
6BE6 6SQ7
6AL5
unmarked tube 12AT7 perhaps


https://i.imgur.com/H75zSH9.jpg

https://i.imgur.com/ZaPPZgw.jpg

https://i.imgur.com/a2j1pCY.jpg

No mention of the Radio in the SAMs, and nothing but a serial # on the radio chassis :/

I would not have thought it would be so hard to find info for the radio part :(

Granted, I am getting a bit ahead of myself, as I will be focusing on the TV part first, and this will take a while, but there is no audio output in it and it needs the radio working for sound. :(
The Hammond 290AX Power Transformer SEEMS to be the right type for it, but as in the TV, the radio also has failed candohm resistors, all burned and opened, it looks like they are what started the problem, they shorted and toasted the transformer to the point that it arced out, it looks like it almost caught fire in there, there is so much carbon.


If I can't find info on the radio ( or be pointed to where to find info ) in the time while working on the TV, I do have this to fall back on.

https://i.imgur.com/zE38A3N.jpg
the radio from the FADA, which is sort of the same. :/

did someone order a power transformer? extra crispy! :D :scratch2::lmao:

https://i.imgur.com/5mWpYbY.jpg

eek!

here is a close look at the damage under the 5U4 socket and candohm1.
https://i.imgur.com/il1O5tw.jpg
gonna need a new socket.

i removed it and took it apart.
https://i.imgur.com/HsRbW5s.jpg
TOAST
there is no info on aside from a Hoffman part # and who made it for them, LONG gone...
in the FADA radio like it, in that position the resistor is 47 ohms. but THAT setup has a filter choke where 42 ohms, this has none, and in the place where candohm2 in the Hoffman, the FADA has a 5.5k.

If i cant find info for this and go this way as done in the FADA, i may have to up the values a bit to adjust for there being no filter choke.

Correction, The transformer needed is Hammond 290CX not 290AX :O
They are pretty much the same, except for that the CX has 2 more amps on the 6.3v heater winding than the the AX, and when I added all the tubes up, it was too much of a load for the AX having only 2.25A, the CX has 4.5.

Took apart both candohm resistors, the 2nd one is mostly intact, (still bad) and seems to be about 3k, or used to be, which is very close to what is in the FADA Radio schematic (3.3k) at that point.
So, making a guess of 3-3.3k 10w chassis mount resistor for here?

Candohm 1 is completely destroyed, burned and blackened, wire on it broken in many places, looks like it was arcing.

For this, I will just have to see what works, 50/70/100 @ 10w.

There is always some give and take in tube stuff, so it should not be hard to get this going if no info on it can be found.

It's pretty clear what happened to it, capacitor failure, plus lack of fuse protection, this coupled with the fact who ever was using it was not paying attention to it and let it burn up.

Evident by the cathode capacitor for the 6V6GT has exploded, and it's paired resister is burned out.
This caused bias to raise above normal and stress already weak electrolytic capacitor,which shorted, overloading the Candohm which shorted and took out the transformer, had the makers put a fuse in there, this chain would have been broken.

Oh well. :(

Mouser is about to ship the parts for the TV chassis.
So I can get a start on that, at least.

The first TV I ever worked on professionally was an RCA portable. The owner had allowed a beer to spill down the back which found its way into the power transformer. It looked like the power transformer out of this radio Yamamaya is working on. Fortunately, the electrolytics and the power resistors were OK. I also had to replace the safety glass. There was a circle shaped indention in the safety glass which roughly approximated the bottom of a beer can. Hmmm.

“ cathode capacitor for the 6V6GT has exploded, and it's paired resister is burned out.”

Imho, a shorted or gassy 6V6 might have started the whole unfortunate chain of events :scratch2:

jr

FOUND IT!!!!
SAMMs 221-6
however this Set seems to be a hybrid... :O

I look up the chassis number on the sticker on the back of the unit and get pointed to SAMs 201-5
which has just the TV, and pretty much matches.
But just by sheer luck I found the combo 221-6 which has the radio and phono, TV is almost the same, slight differences.

Weird.
It says candohm 1 500 ohms 7.8 watts, candohm 2 2.6k 6.5 watts.

Transformer
sec1
695vct .130ADC
sec2
5vac 3A
sec3
6.3vac 3.7A

Hammond 290CX specs
650/550Vct @ 100 mA
Secondary 3 6.3Vct @ 4.5A
Secondary 4 5V @3A

https://i.imgur.com/FWTzNOB.jpg
https://i.imgur.com/ArZ74fk.jpg

all prepped and ready to haul upstairs to my work room!

A bit of more good news for the Radio section, now that I have the Sams, i was able to check the Audio output transformer , and it seems OK, it says DC resistance @ 380 ohms and my DVM says 355, so I guess it was not damaged! :banana:

I do wonder about the strange white stuff that I saw on the FBT, not seen that before.

But as mentioned, the general resistance check seemed OK going by what was in the SAMs, just not sure what to make of it.

Just wait till I get horz/HV up, see what happens?

Give it a good deep coating of super corona dope and then try?

Whatever that white crud is, I'm kinda afraid to touch it for fear of causing unneeded damage, but I don't think a few layers of SCD would hurt.

And if all fails, and the FBT is problematic, ETF does have 3 compatible replacements.

some more good news,
I MAY not have to buy a power transformer

this MAY work.

https://i.imgur.com/pteUqEl.jpg

restoration started.

https://i.imgur.com/UcO6drS.jpg
before

https://i.imgur.com/0eEXVCG.jpg
after
notice the exploded bumble bee :O

https://i.imgur.com/VC2A2bR.jpg

The Sam's I have I think has the radio chassis covered in it, I can send you the radio portion of the service data. :yes:

Yes, I believe it does, I'll take a look for sure.

My Sam's stash seems to be an odd mixture of Midwest, East Coast and West Coast makers, which is kind of odd, seeing as they came from a shop here in the Midwest... :scratch2:

I did eventually find it, it's spread between 2 separate SAMs folders.

the TV chassis matches what is in 201-5 but is the TV only, no Radio. :(

just by random chance looking on eBay I spotted the right folder for the combo 221-6 which has the radio but does NOT match the TV chassis.
close, but has critical differences

OK... this is a bit strange...

the SYNC SEP circuit has been altered. :O

https://i.imgur.com/wYtJAc5.jpg

clearly at one point, a resistor fried and was fixed, bit they never removed the burned one, SLOPPY!! ( Crappy soldering too )

BUT

https://i.imgur.com/KqSbiF6.jpg
SAMs shows a 82k to power and 18k pulldown.

but what is in there NOW is 820k and 1m :O
hmmm

leave as is? or put it like it says in the SAMs? :O

Leave it. The set worked with it that way and it could have been a production change. If you have sync problems later you know one place to look.

221-6 is the one I have, so I could send you the Radio portion of the Sam's I have, and you could use the TV portion you have and you should be able to get by with those two. :yes: :thmbsp:

It's alive!! It's alive!! hahahahahaha!

- does best Frankenstein laugh

https://i.imgur.com/RZwqCKc.jpg
https://i.imgur.com/afNm19c.jpg

I have reached my week 1 goal of being able to power it up far enough to see Horz sweep at the HOT.

next is getting HV up.

still more caps to replace :o

i was able to get both folders from the Sams site, tks for the offer.

No problem.

Im just curious, but what was different between your unit and what was in the Sam's Folder that was supposed to be for your unit as far as the TV section went?

I'm asking because if it was something like the tuner being a different unit than used in yours or a slightly different tube line-up than yours had but the overall circuit layout was the same then I would just use the Sam's for the combo unit and just note on the Sam's the differences (whether it be tube line-up differences or tuner difference or whatever) and you should be good to go.

I've had to do that plenty of times myself when I've worked on some of my old radios in my collection where there were some slight component differences from the service data I had on hand but the basic circuit layout was the same (my RCA 5T was one example) and all I had to do was just note on my service data that there were some slight production changes made to the unit between the time the service data was made and the time that my unit was made that didn't make it into the service data.

Differences in the voltage divider layout and filter caps used, slight diff in Vert & horz out circuit.
Video out also different, 6AH6 VS 6CB6.
And yes, tuner is different,
just slight changes all over, enough to be annoying! :P