Stay away from??

[TVTim]

Okay. I've read posts about various brands that say, that was from the such and such era.

For brands like RCA/Zenith/Panasonic/SONY, which years or models are the ones to completely avoid.

I'm looking 1975 to 2000.

Any input is GREATLY appreciated.

Thank you!!

[zeno]

Avoid Zeniths after apx 1992 & "digital" processed sets
(marked Digital System 3 )
Avoid most Sonys apx 1974-1977 12" 17" 19" & 21"
Avoid RCA TX81, TX82, TX825 chassis
Panasonics are safe.
As a rule the easiest to deal with are solid state sets up to
the late 80's. Tube & hybrid sets tend to have multiple
problems.

73 Zeno

[ChrisW6ATV]

Originally Posted by zeno

Avoid most Sonys apx 1974-1977 12" 17" 19" & 21"

If you do not mind my asking, what is worse about this era of Sony color sets compared to earlier and later ones? I remember working on an absolute dog 12" color Sony set about 1983-84, but I think it was an earlier one (1970-72).

[zeno]

Originally Posted by ChrisW6ATV

If you do not mind my asking, what is worse about this era of Sony color sets compared to earlier and later ones? I remember working on an absolute dog 12" color Sony set about 1983-84, but I think it was an earlier one (1970-72).

The first Sony colors were not bad. The only thing odd
about them was they used separate HV & H sweep stages.
They switched to an SCR the SG613 abt '74 & they were
dogs to deal with. I did time at Sony service in '76 IIRC.
Even they couldnt reliably fix them. Most of them got the
whole H/V/HV board replaced along with the power supply parts
damaged. The customer would get a bill for a hand full of
small parts. No shop in my area would touch one, it meant 2
50 mile round trips to Boston if you had a dead one.
After that they switched to a conventional hoz design &
for the most part became as easy to fix as most sets.

73 Zeno

[rca2000]

I'll try and explain this a bit more...others feel free to add more.

The aforementioned Sony sets with the "SG-613" GCS device (Gate controlled /turnoff switch), (occasionally an SG-264A was used) were VERY difficult to work on, because the GCS has ONE VERY bad attribute: it will SELF_DESTRUCT, if it loses gate drive--even if only for a BLINK of an eye !! Like an SCR,m they are turned on by a gate and STAY ON, until a reverse-pulse is applied to them. But, UNLIKE an SCR--a GCS can ALSO be turned OFF by that same gate---this makes them suitable for an amplifier ckt, at least a class C horizontal out ckt. Well.. "kind of suitable".


They, in reality, are NOT really suitable, because unlike a Bipolar transistor or even MOSFET or IGBT, they often fail in a horizontal ckt,. MUCH more than other devices, including tubes. Like a tube--when the drive is not there--they conduct "full-bore" , BUT UNLIKE a tube--they CANNOT handle this severe overload. Not even for a millisecond. Whereas all of use have seen an HOT "red-plate" because of even a slight loss of drive or such---we all KNOW they can "take it" for a short time, at least for awhile. Of course--this cannot be allowed to last--as it WILL kill the tube and more importantly its "load, meaning the flyback, in a short time if left this way. So, we go after the drive ckt, and fix it, and all is well. If, while chasing this problem down, there is a quick period of drive loss, we discover it, and correct it. if it last a few seconds or less--no harm is usually done.


BUT on a GCS horizontal ckt...ANY...and I mean ANY interruption or even reduction of the drive and ...BAM !! Out goes that GCS--WAY before you have time to discover why too !! They INSTANTLY short from "cathode" to "Anode", if that can really be considered the right terms for their elements. Think of all of the multitude of sets we have worked on over the years--with intermittent drive issues--usually, IF you catch and fix this in time-no harm is usually done, Sometimes, it may be a good idea to replace the H-out anyway, "just to be sure" all will be well, but often if you resolder the drive transformer of replace the cap in the base ckt--all will be well--for a long time.

But on these GCS Sonys---you get just ONE chance---to get EVERYTHING right--and I mean EVERYTHING !! Just a TINY problem with a glitch in the H-drive and BAM!! Out goes that GCS and fuse, and usually the B+ reg too and maybe more !! SO it was VERY difficult to fix one. Often, we would THINK we had one fixed, and POW !! Out it would go, ANd those Sony GCS'S were NOT cheap. Unlike Normal FET or Bipolar transistors, they did NOT get "cheaper" as time went on, either, and you could NOT use ANY other type than Sony !! If you id--you were SURE to be disappointed !! I fixed a FEW of these sets in years gone by--but do NOT really want to work on ANY more of them. By now--they are OLD, OVER 35 years I think--since Sony used them and I do NOT think ANY of the GCS sets would be fixable with all of those old caps. And Sony Trinitron tubes are NOT really known for their long-life, anyway...

So...STAY AWAY from Sony sets made from about 1973-1978 or so...unless you are a SEVERE masochist !! Maybe THIS will make things more clear for you all.

[zeno]

Originally Posted by rca2000

I'll try and explain this a bit more...others feel free to add more. ETC........

Add to that the SG613 was about $25 plus the other parts damaged
every time you tried it you rolled the dice for $40 or more.
You could not return a "new defective" one. There were a few
common problems but the few people doing them kept
hush hush. When we were charging $50 the few Sony folks were getting
over $100 to do any Sony. There was a trouble shooting sheet for them, never seen one. Anyone got one? I didnt do many colors at
Sony, one of the guys advised me not to become the color TV
man unless I wanted a drinking problem. It was a specialized crew with
one of each doing
Color TV
B&W TV
Video
B&W TV
Audio
Radio & misc smalls
Parts man / janitor
one useless manager with a huge office
two gals for paperwork etc
We would drift around a bit when caught up or needed a change of pace.

73 Zeno

[ChrisW6ATV]

Originally Posted by zeno

The first Sony colors were not bad. The only thing odd
about them was they used separate HV & H sweep stages.
They switched to an SCR the SG613 abt '74 & they were
dogs to deal with...

73 Zeno

Originally Posted by rca2000

I'll try and explain this a bit more...others feel free to add more.

Thank you both for the detailed comments about those Sony sets. That number, SG-613, is very familiar to me. I may have even swapped out one in the past in some set; I have definitely seen it more than once. It looks like a TO-3 case but about 30% smaller, and narrower if I remember right.

[Zenith26kc20]

We fixed many of the gate switch Sonys. The key to getting them repaired was to break the set "in half". Using a square wave generator to feed a signal to the power supply enabled you to get it working. The horizontal stage failed repeatedly due to the horizontal drive IC starting slow. Somewhere are the rest of my notes but you had to use a variac on the set with the power supply disabled (jumpered) and at 18 volts of B+, the chip HAD to start producing horizontal drive. If it needed 20 or more it was bad. These sets had another problem. The 330 pf across the gate switch loved to short out.
I always wonder why Sony made such an insane TV.
The Zenith 9-160 modules could drive you nuts sometimes too. We had harness problems galore on those sets. THe 9-181 sets with "kick start" were somewhat fun. If the twist lok electrolytic opened up on the 181, the kick start would burn up after a few seconds.
And don't forget the Magnavox "Star" system with a AA battery in the tuner.....

[radiotvnut]

I'd also avoid Mitsubishi's from the late-'80's on up. Ones from that era used not so great electrolytic capacitors that will literally leak electrolyte all over the PC board and eat the traces off the board. The last Mitsubishi I took in for repair was an early '90's 27" set that had no less than 25 capacitors that were bad in some way (many were leaking electrolyte). The customer didn't want to spend much on the set and I ended up junking it. The older Mitsubishi's up until the mid-'80's were great TV's and the CRT's usually hold up well in them.

[davet753]

Originally Posted by radiotvnut

I'd also avoid Mitsubishi's from the late-'80's on up. Ones from that era used not so great electrolytic capacitors that will literally leak electrolyte all over the PC board and eat the traces off the board. The last Mitsubishi I took in for repair was an early '90's 27" set that had no less than 25 capacitors that were bad in some way (many were leaking electrolyte). The customer didn't want to spend much on the set and I ended up junking it. The older Mitsubishi's up until the mid-'80's were great TV's and the CRT's usually hold up well in them.

You are so right. I had forgotten how bad the Mitsubishi sets were. I remember their projection TV's were the only brand that we refused to service.

While likely in the minority, I never liked working on Sony stuff. Their parts were not easily obtained (unless you were an authorized Sony shop) and the only thing higher than their retail selling price was their parts prices.

Definitely agree on the Zenith's from the 90's. I worked for a hotel company that bought 100's of them over a six month period about 94 and I spent the next couple of years hauling dozens of them to the local Zenith dealer (who literally stayed in business doing warranty work). Not all the tv's went bad, but I swear every remote did. I learned they had bad solder joints and I would take home a sack full at a time and fix them myself to save us some money on them.

A couple of other things to avoid on any brand set from that time period. First, a practice called tiering started with the makers around the late 80's. The low tier was the cheapest quality and sold at Walmart and Sams. Stores like Best Buy and HH Gregg got mostly middle tier and some top tier. Specialty stores and the few old dealers left got top tier. If there's anyway you can find out where it was sold, avoid the Walmart versions.

Second, a number of stores specialize in "Factory Serviced" sets. These were sets returned from other stores with problems and sent to a reconditioning facility, which supposedly repaired them like new. I know from personal and business experience that they were a real crap shoot and often wern't worth buying. They usually had a sticker on the back saying "Reconditioned" or many of them had a "R" heat stamped into the plastic backs.

[Robb]

GOOD INFO.
I generally only collect smaller table top sets from 1970-1985-ish.
Any other sets from this time period to stay away from ?

[radiotvnut]

I recall many Panasonic/Quasar sets from the '80's with bad flyback transformers. I recall the TLF14423F flyback that was used in 25" Panasonic/Quasar and some GE sets that were built by Matsushita. The reason I remember that number is because I had to change out the flyback on most every one of those sets I got. Those Panasonic TV's from that era were also common to have weak CRT's and bad soldering. There was another Panasonic chassis that was used in some '83-'84 13" and 17" GE branded TV's (BC chassis) that were common flyback blowers. Also, the cheap brands from the '80's (Samsung, Goldstar, Emerson) were known to lose their flyback transformers. I recall those '80's Emerson TV's (13" and 19") that had the chassis mounted sideways in the cabinet and I was replacing flyback transformers in those when they were only a few years old. Even some Sony's from the '80's and '90's liked to eat flyback transformers.

OTOH, except for the RCA flyback fiasco of the early '80's, I don't recall RCA sets from the '80's and early '90's eating flyback transformers. The 13" and 19" NAP (Magnavox, Sylvania, and Philco) sets from that era also seem to be reliable.

There was one Sylvania chassis (also found in Magnavox and Philco) from the early '80's that had a problem with failing flybacks. The chassis was E31 for the 13", E32 for the 19", and E34 for the 25" sets. I own a 19" E32 that had a bad flyback when I got it and I managed to find a used flyback to go in it; but, I'm a little nervous about the used flyback failing.

[TVTim]

Originally Posted by radiotvnut

I own a 19" E32 that had a bad flyback when I got it and I managed to find a used flyback to go in it; but, I'm a little nervous about the used flyback failing.

You did a youtube on this set, didn't you? I had a Magnavox that looked just like it. Donated them in 2000 when I moved to Pennsylvania. It was a decent set and I would love find another one of them.

Selling the the Sylvania??

[TVTim]

Wow, am I glad that I asked this question.

Lots of great stuff here. I will definitely be copy/pasting all this into a Word doc for safe keeping.

Thank you everyone.