which chassis was the best ?

[rca2000]

In regard to the moto JA sets....I think the biggest problem is that techs were NOT used to a SMPS power supply back in 1971. It must have been a LOT of fun checking a board over, finding a shorted SMPS out transistor, changing it , and applying power, just to hear that POP!! the instant you powered the set up--due to a shorted load or stuck oscillator. Keep in mind--these guys were still seeing totally tube sets EVERY day....and any SS sets was still strange to them.

Today--that JA SMPS power supply is old-hat--and most of us who have worked on sets for the last 30 or so years would find it's circuitry pretty familiar--and easy to deal with. A relatively simple forward-mode switcher, with horiz. rate locking. I recall fixing a few JA sets, one was a 19 incher. Have NOT seen one in over 25 years though !!

[Jon A.]

I guess it's hit or miss with sets such as the CTC38. Seems they got some undeserved bad PR like the Pinto/Bobcat duo did. Lots of other cars at the time were just as likely to burst into flames when rear-ended.

[zeno]

Originally Posted by rca2000

In regard to the moto JA sets....I think the biggest problem is that techs were NOT used to a SMPS power supply back in 1971. It must have been a LOT of fun checking a board over, finding a shorted SMPS out transistor, changing it , and applying power, just to hear that POP!! the instant you powered the set up--due to a shorted load or stuck oscillator. Keep in mind--these guys were still seeing totally tube sets EVERY day....and any SS sets was still strange to them.

Today--that JA SMPS power supply is old-hat--and most of us who have worked on sets for the last 30 or so years would find it's circuitry pretty familiar--and easy to deal with. A relatively simple forward-mode switcher, with horiz. rate locking. I recall fixing a few JA sets, one was a 19 incher. Have NOT seen one in over 25 years though !!

The transition was interesting. Started with Zeniths & Admirals first
since we sold them. Others were referred to other shops that sold that
brand. RCA was next due to numbers & proved easy. Then Sylvania,
GE & the rest of the US sets. Jap sets were next in the late 70's.
At first nobody liked them including me. After a few years I never
wanted to see a tube TV again & left them for the old farts. Much easier
to deal with & the recall rate fell to near zero.
You are 100% on the SMPS. The first JA set I saw I had no idea
what it was. It even looked strange...... I started trouble shooting it
but the boss stopped me & got a board at Moto Boston. Said by the
time I got it going I could fix five other sets & not do anyone any favors.

73 Zeno

[Electronic M]

I think the Motorola Quasars deserve an honorable mention. When I was growing up my folks had one of Moto's last ones (~1976) that kept chugging along into the early 90's. IIRC the story of it's death and a vid of a similar set (mine might have been a hybrid) is in the what I want link in my sig. It was a good set, and it may have ran a few more years if I wasn't so curious as a kid... It was about as good as my hybrid Zenith CC set is now performance wise.

[andy]

...

[DaveWM]

PCB damage by ham handed techs seems to account for most of the problems I have seen as well, but I have run into some that had a lot of crysalized looking solder and a few with really bad tube sockets (literally crumbling). I prefer to work on unmolested pcb, but if its been hacked then not so much. I ran in to one where jumper was used to aid in a tube ground, it was soldered to the center post of a tube socket on the pcb, the other side still had the alligator clip, attached to the metal chassis. I love my 26DC56 zen SS set, its so well built. My sylvania SS seems to have a better pic but that may be just because I have not spent a lot of time messing with the zen setup.

[rca2000]

If we REALLY want to get honest with ourselves....then the flat-chassis SS Zenith sets we love--ALL of them...including the BW sets with plug-in boards--are actually a "hybrid" between hand-wiring and PC board construction , as more than half the circuitry, most of the low-level stuff--is on those boards and the power devices all plug in.

[Jon A.]

Originally Posted by rca2000

If we REALLY want to get honest with ourselves....then the flat-chassis SS Zenith sets we love--ALL of them...including the BW sets with plug-in boards--are actually a "hybrid" between hand-wiring and point-to point wiring, as more than half the circuitry, most of the low-level stuff--is on those boards and the power devices all plug in.

True, just no burnout-prone tubes to deal with. Also, the dura-modules are too small to flex from heat. The transition time was then, and Zenith did it best.

[wa2ise]

I liked the picture the RCA comb filter chassises (CTC101, CTC111, CTC121, CTC131) produced. Though the CTC101 had that infamous flyback.

[Jon A.]

So the CTC110B in my 1982 RCA doesn't have the comb filter?

[rca2000]

Originally Posted by Jon A.

True, just no burnout-prone tubes to deal with. Also, the dura-modules are too small to flex from heat. The transition time was then, and Zenith did it best.

IOW_--the BEST OF BOTH WORLDS !!

It is no WONDER we all admire them as much as we do...and of course a nearly indestructible tube helps too!! Kinda like the "3800V6" of tv sets !!

And though not color--the "tin can Zeniths" as they are called here--find a special place in my desires too. I have several of them, including I think 3 SC sets and a couple "bug eye" models. Altogether--I think I have 10 or so of them.

Face it...until the mid-1970's..Zenith was in class by ITSELF-- as far as tv's-and for that matter console stereo chassis_ were concerned. Their regular radios are NOT that special though, compared to tv's and stereo chassis...

[rca2000]

Originally Posted by Jon A.

So the CTC110B in my 1982 RCA doesn't have the comb filter?

It may. A LOT of them after the 101 had them and likely nearly ALL of the 131 and after high-end chassis, like the CTC-169 do.

[Electronic M]

Originally Posted by Jon A.

True, just no burnout-prone tubes to deal with. Also, the dura-modules are too small to flex from heat. The transition time was then, and Zenith did it best.

Prone might be a bit harsh. My daily driver sets usually only need tubes replaced every couple of years or more, and usually it's the horizontal output or some other high power tube. Signal tubes seem to be rather long lived.

[maxhifi]

My 16 inch zenith chromacolor hybrid portable needed two tubes in 20 years of ownership and lots of use - the burst oscillator and the RF amp in the tuner. Tubes have been pretty kind to me.

[rca2000]

Originally Posted by Electronic M

Prone might be a bit harsh. My daily driver sets usually only need tubes replaced every couple of years or more, and usually it's the horizontal output or some other high power tube. Signal tubes seem to be rather long lived.

I cannot TELL you how many old sets I have seen with most of the power tubes (horiz, vert, video HV rect and audio outs) ALL original, particularly BW "tin can Zenith sets". LV rect tubes--(5u4, 3dg4, etc) NOT as often..