I no longer have this set.

I have basically the same set except mine has mechanical tuners.

Edit: never mind, found my thread and it's a pushbutton also, model C388. Cabinet is similar or the same though.

The Japanese made some good stuff early on, Sony being the biggest exception.

Sony was arguably the highest quality Japanese TV of the era. What problem with Sony have you experienced that leads to the exception?

In my nearly 40 years of messing with TVs, working in a shop, and collecting, I've seen lots of Japanese crap - Toshiba (flybacks in tube sets, bad yokes in Solid State stuff), NEC (Tube sets - lots of bad connections and sockets that would flake apart) and Sharp (Open IF cans, early Sharp-specific chips were crap) were the worst. IMO, Sanyo and Sony set the bar - gimme a KV-1710 or 91C90 Sanyo any day over anything of that era.

One exception to the Sony opinion above - the multi-standard (PAL/SECAM/NTSC) sets Sony made were a nightmare - flybacks on the late 70s sets, and the universal power supplies were simply odd.

Sony was arguably the highest quality Japanese TV of the era. What problem with Sony have you experienced that leads to the exception?

In my nearly 40 years of messing with TVs, working in a shop, and collecting, I've seen lots of Japanese crap - Toshiba (flybacks in tube sets, bad yokes in Solid State stuff), NEC (Tube sets - lots of bad connections and sockets that would flake apart) and Sharp (Open IF cans, early Sharp-specific chips were crap) were the worst. IMO, Sanyo and Sony set the bar - gimme a KV-1710 or 91C90 Sanyo any day over anything of that era.

One exception to the Sony opinion above - the multi-standard (PAL/SECAM/NTSC) sets Sony made were a nightmare - flybacks on the late 70s sets, and the universal power supplies were simply odd.
I'm going mostly on other experiences I've read here. I don't think I've ever had a Trinitron with a strong CRT, apparently they don't lend themselves to rejuvenation and those SG-613 sets are so easy to blow out. Also, they use a lot of unusual parts. Good luck finding subs for anything aside from caps and resistors, especially the CRT.

I'm going mostly on other experiences I've read here. I don't think I've ever had a Trinitron with a strong CRT, apparently they don't lend themselves to rejuvenation and those SG-613 sets are so easy to blow out. Also, they use a lot of unusual parts. Good luck finding subs for anything aside from caps and resistors, especially the CRT.

SG613s, SG608s and other Sony-unique parts are still available - the problems most folks had with SG613 sets was their ignorance to how the circuit operated and their unwillingness to troubleshoot further. Bad SG613 with a bad damper diode? Most folks stopped at the SG613, and when it blew again, gave up. I've met several experienced techs that were like that - give them any other set and they'd fix it almost immediately, but with "SONY" staring them in the face, it's like they forgot how to troubleshoot. Never forget the basics - bring it up on a variac, check your power supplies, and then use a 100W bulb to limit the B+ until you get things settled. I never saw a flyback bad in those early sets - usually it was the SG613, a SID30-15/GH3F diode, some bad connections on the horizontal driver transformer and driver transistors (2SC1124's - odd little bastards, we ordered them 10 at a time, as the ECG and other replacements fell short...). Replace that, get those 160V electros replaced, and all was well...

Sony gave everyone the tools with the manual, but most folks used only the Sams to troubleshoot with - big mistake. Sams didn't highlight the different SG613 markings/diofferences like the Sony manuals did. The irony was that Sony (at least their California HQ) had manuals for only $5 shipped. Beautiful manuals, all pink and white...with the manual came all the service bulletins (usually 2 or 3, but some sets had 30 or more!) and any parts bulletins to update, correct or provide the latest sub for parts. I've got tons of them left over from our shop - most are dupes, as the same part in multiple Sony sets meant you got the same bulletin several times over the years.

Fix the horizontal on most, change out the dang 160V caps (Matsushita and Nichicons) and you'd have a set you'd never see as a callback.

470BEBP22 Sony CRTs did go bad, but not any more frequent than others, and a traditional brightener wouldn't do. Many developed H-K shorts, so easy isolation of the filament with a GE horizontal driver transformer (1:1.1 ratio, EP77X-something, I forget..) We replaced a few - easy peasy, as once the H-Stat was adjusted, all the dynamic convergence fell into place. Later (1980-on) Sonys had the dang pincushion magnets and the templates to use for the starting position. Mitsubishi and even some US made sets were similar, so the pain wasn't just Sony.

I've seen only two Sonys that never left the shop - one was a 19" lightning strike write-off/gimme set, and the other was the casualty of a house fire - the back melted onto the set - a little 12 incher with the tuner under the CRT. We cut the back off, found out the extreme price (back, logo, two attachments, all coming from Japan) and shot an estimate. The insurance company said junk it, but the SET OPERATED NORMALLY! No repairs needed, it just needed a back. We relegated it to one of our "run" VCR benches for 9+ years without failure.

I will fault the Sonys with the STK regulator modules - so much simpler to follow the crowd, but what POS-es they were. Any thunderstorm ( a common occurrence here in the summer) and they'd crap an STK. We'd replace the STK, add a MOV after the fuse, and see it again for only a fuse replacement. Add to this the IF soldering issues (easy, but from the factory in Mexico problem - should have fixed it there...) and you had a steady stream of sets coming in. Our last few years were the dang MX0841 sets - either them or the 2SC4927's - again, mostly lightning strikes, and after the Sony 04-2mod, never a problem again.

We made more money off GE, Zenith(name the problem, we saw it...), and cheapo Sears (bad flys in the Sanyo sets, bad vertical and caps in the Toshiba sets)/Wards(Admiral woes - mostly horiz outputs, and electronic tuning issues)/AOC/Bohsei/Emerson(Caps, chips, and vertical issues)Sanyo/Sharp(Flybacks - mantra was "RTRNF00-what??") and MGA sets (PIP modules, lots of sound issues, etc). Sonys were fewer in the mix, but still there....

Yeah, those SG613s are easier to get than a high-value, fully-insulated focus control or a spare sync separator for my Sylvania Superset. I've been looking for the latter since shortly after I got the set well over a year ago.

So the Sonys got singled out along the way, kind of like the Pintos and Bobcats did for catching fire when rear-ended when many other cars of the era could go up just as easily. Still, I don't like that the CRTs go bad easily, don't rejuvenate well and can't be subbed with another brand. I have a Sony parts set with a CRT whose code starts with 520; not a common size.

So lots of problems with Zenith huh? I'm not really surprised. Mine was troublesome the whole time I was using it, and apparently the horizontal picture shift is common and can't be corrected. My Electrohome console produces a nicer picture, has a far nicer cabinet (a far cry from the Zenith's crap plastic, I'd rather particle board) and hasn't given me a lick of trouble since I fixed the cold joint on the left horizontal blue control and set it up.

I though bringing up a SS set on a variac was a no-no.

Yeah, those SG613s are easier to get than a high-value, fully-insulated focus control or a spare sync separator for my Sylvania Superset. I've been looking for the latter since shortly after I got the set well over a year ago.

So the Sonys got singled out along the way, kind of like the Pintos and Bobcats did for catching fire when rear-ended when many other cars of the era could go up just as easily. Still, I don't like that the CRTs go bad easily, don't rejuvenate well and can't be subbed with another brand. I have a Sony parts set with a CRT whose code starts with 520; not a common size.

So lots of problems with Zenith huh? I'm not really surprised. Mine was troublesome the whole time I was using it, and apparently the horizontal picture shift is common and can't be corrected. My Electrohome console produces a nicer picture, has a far nicer cabinet (a far cry from the Zenith's crap plastic, I'd rather particle board) and hasn't given me a lick of trouble since I fixed the cold joint on the left horizontal blue control and set it up.

I though bringing up a SS set on a variac was a no-no.

As to the focus control most were 10-20 Meg in value. We used a Zenith control in most sets - 63-6444. It allowed for modest adjustment and easier replacement. As to the sync separator, do you have a WTB ad in the VK classifieds? Is it a chip or transistor? Sync Separator is pretty generic..

520 jugs re 20" tubes - some 19V tubes are actully 20". KV20SXX sets used them - most had the bar tuning on them - we saw a few - most were simple fixes.

As to variacing a SS set, you bring the AC up to 90V with the Variac, and most sets will come on at this voltage - albeit with reduced sweep. With the lower B+, shutdown circuits aren't tripping yet, so you can see if the set will operate once the shutdown problem(s) are fixed. Standard procedure with Transistor output sets. Shutdown problems could be regulator feedback loops, HV too high, HOT collector current too high (most used a 1 ohm resistor to measure - it gives 1:1 V:A ratio), as well as other shutdown problems such as no horiz drive, no CRT screen voltage (shutdown to prevent arcing), high B+ and other B+ issues (Hitachis shutdown if there is too much ripple in the B+).

If the set runs at 90V, we'd clip a 100W bulb in series with the B+ at the HOT - this solved the problem of blowing the HOT if you had a bad safety cap, poor Horizontal drive/wrong waveform, a short in one of the scan derived supplies (secondary of the flyback), a short in the flyback (it'd get warm quickly, but not eat the HOT - see Sylvania "white flyback" issues...).

There's a good monograph from NAP on power supplies - I have part II, the switching supplies section. There was also a 19 minute video that accompanied the monograph for training - I used to have it too. I got it from ISCET - apparently NAP had them left over from service seminars, and gave them to ISCET, who gave them to us members. It's a great information source, and the linear monograph shows how to do the variac thing for most sets.

Zenith TVs were problematic because they were sold in volumes here by two home centers and dealers, not to mention the Navy Exchange. All the barracks were full of them. My brother once bought 5 pallets of System 3 sets at a DRMO auction and restored half of them, and Dad got the rest for parts...Being in a Navy town, we saw it all, although I've never seen either a Coronado or Electrohome set....but everything else. like ELKO sets from Europe, all-in-one boomboxes from Sharp and Wards, and even a older mirror lid set from the 40s. Dad used to get Motorola VT-71's and restore them and sell them, and he even brought several Predictas back to life. NAP, believe it or not, had replacement parts for Predictas up until 1990 or so. We got replacement multi-section caps for Predictas from NAP - it was a modern replacement that upped the value on two sections of the cap...Mallory had dropped their replacement by then.

I've got a few jap deltagun 520xxP22 tubes. The jap tubes measure bulb size in mm, so divide by 10 and you have the size in cm, or you could divide the ID # by 25.4 to go directly to inches...

I thought the Zenith 63-6444 control doesn't have the nylon mounting tabs necessary for isolating it from the chassis on many sets but the 63-7210 does. Seems the 63-9967 is insulated as well but I don't think the mounting material is as strong. Besides, my Sylvania requires one with a much higher range. My Electrohome uses the same crap focus pot design as the Sylvania but the resistance is very close to that of a Zenith 25DC56.

I've been looking on eBay for a sync separator IC. The Sylvania's chip crosses to the ECG820.

Japanese/Korean CRT size numbers are a little confusing to me, especially those on Sony CRTs. I often don't know if the number means viewable or actual size.

Really cool set Jon. Congratulations on your find!

I'm not a fan of early Sony stuff. I would be if I ever came across one with a good tube.

I'm not a fan of early Sony stuff. I would be if I ever came across one with a good tube.
If I found one I like enough I'd try to sub the CRT from a newer Trinitron. Considering what I read above it may work. I just parted out a flat-face CRT set whose CRT code started with A51; it measured almost the same diagonally as the 520 Trinitron CRT, only a fraction of an inch difference. Not a very good comparison but it's all I had on hand. As far as I know there are no A52 CRTs.

By the way I found out how to use my digicam's wifi with the iPad so I shot a bunch of new photos. Big improvement over the crap iPad camera.