IHVT vs. separate tripler and flyback transformer

[radiotvnut]

In the 1970s, most solid-state color sets and some hybrid sets used a small flyback transformer that fed into a solid-state tripler, which bumped the voltage coming out of the flyback to 25-30KV. I've seen a lot of these triplers fail and the most common failure modes are an internal short that trips the circuit breaker, insulation break-down that causes the tripler to arc to the chassis, and the built-in focus divider in triplers that were so equipped would fail.

On a few occasions, I ran into a shorted tripler that took the flyback and HOT with it (once on a flat chassis Zenith, 2-3 times on a vertical chassis CC2 Zenith). I suspect that happened because the owner either held in the circuit breaker, or kept rapidly resetting the circuit breaker, in hopes that a picture would appear, when all they were really doing was increasing the repair bill on their set.

By the early '80s, most everyone had switched to an IHVT-style flyback, which consists of the flyback, tripler/HV rectifier, focus divider, and often controls for focus and G2 adjustments in the same package. This system was more compact, but I don't think it was as reliable as the separate flyback and tripler (trying to fit too much stuff in a small package). The first Sylvania set that I remember with an IHVT was the E32/34 series chassis, and those liked to go "POP!" Then, there was the early RCA IHVT that failed left and right, but RCA made good on those. The flyback on Zenith 9-160 boards liked to arc out and blow up other stuff. The flyback in cheaper Korean and Taiwanese imports were also not very reliable.

Back in the '90s and early 2000s, I could get NTE, ECG, and SK generic flyback transformers for most of what I needed, but today, I know of no one who makes generic flyback transformers. So, when the flyback goes in your '80s, or later, set, then that will probably be the end of the TV.

The last generic flyback I got was a dud and I actually didn't want a generic flyback. It was for a big RCA 36" console (CTC179, I think) and I called Tritronics and told them that I wanted an RCA original. Instead, they sent me some cheap generic "no name" job that literally blew up after about 15 minutes of use. I called Tritronics and burned their ear, to which they swore they sent me an RCA original, but they didn't. I finally tracked down an RCA original and all was well.

The most reliable IHVT-style transformers that I recall seeing were the ones in '80s RCA sets (after the early '80s flyback fiasco), the ones that Zenith used on the 9-153 module (1st System 3), and the ones used on the C1 and C2 NAP (Magnavox) chassis. Flyback transformers in Sanyo and Toshiba sets held up pretty good, as did the flyback transformers in RCA/GE CTC175/76/77 sets. The flyback in the GE "PC" chassis seemed reliable (I think I only ran into one bad one).

The worst were '80s Sharp and Panasonic, and Korean/Taiwanese sets (GoldStar, Samsung, AOC, and Sampo, Orion/Emerson), and mid-'80s to '90s Hitachi. 21st century RCA (M134C, ITC008, ATC series chassis) also liked to eat flyback transformers. There was one '80s Panasonic 25" chassis that was also used in Quasar, some GE, and some JCPenney sets that you could just about count on the flyback being bad in (part number TLF14423F). I've also replaced a good many shorted or arcing flybacks in Sony sets from the '80s and '90s.

[Electronic M]

A fair portion of the 80s sets probably still have NOS flys sitting in TV repair shops....a couple of years ago I got a lot of SS TV and VCR parts in a radio club donation auction and I kept the flybacks because I can steal the HV wire off of them for my tube sets.

[JohnCT]

From my experience, triplers failed at a much higher rate than integrated flybacks did (with those exceptions you mentioned).

I think it came down to two things that made a reliable IHVT possible - better HV diodes and better insulation potting compounds. Both of those advancements would have made triplers more reliable as well but I don't know if the upgrades made it to the last gen triplers (maybe they did?)

John