View Full Version : 1985 GE BC-A Color TV


maxm
06-17-2017, 06:56 PM
This is not normally a set I would seek out. I saw it a few weeks ago at an estate sale, sitting outside next to bags of trash in front of the garage and another newer TV. I asked about it and they were happy to give it to me for free. I didn't want it to get trashed so I took it home. No remote was with it.

The set appears to have been assembled in the US, though the main board was made in Japan by Matsushita. I don't see an indication of where the CRT was made.

I would be interested if anybody has more information about this set. Was it a GE design?

It it working pretty well, I was able to get a universal remote to work with it. This is now the newest TV in my house.

Additional photos below:

http://www.tepperaudio.info/photos/GEBCA/index.html

Findm-Keepm
06-17-2017, 07:22 PM
13BC-A chassis, made by Panasonic in Japan, assembled with GE-made tuners and other-sourced (Clinton?) CRTs (note the double labels..). Last gasp Portsmouth-assembled sets, along with the PC and PM chassis stuff. After those, Thomson bought the bunch, and GE got RCA chassis...

Great sets - we saw only lightning strike sets. Rare anymore - haven't seen one in 10 years.

wa2ise
06-18-2017, 07:39 PM
It looks like a hot chassis set that uses a bridge rectifier. It stays hot no matter which way the power plug is connected. The small power transformer probably powers the remote control receive circuits.
http://www.tepperaudio.info/photos/GEBCA/Images/3.jpg

dishdude
06-18-2017, 11:11 PM
It's like two different sets in one! The bottom part is totally Panasonic, phillips screws and all. Move up, it's all GE and held together with hex bolts.

zeno
06-19-2017, 07:00 AM
Uses GE tuner complete with intermitant griplets.

73 Zeno:smoke:
LFOD !

dieseljeep
06-19-2017, 11:18 AM
Uses GE tuner complete with intermitant griplets.

73 Zeno:smoke:
LFOD !

Wasn't that chassis notorious for flyback failure? IIRC, they were $100usd, back then.

Jon A.
06-19-2017, 01:44 PM
This is now the newest TV in my house.
High five!

I was in a house recently where I got bored silly watching a flat screen along with someone else. To make matters worse he was watching golf, yech.
It's like two different sets in one! The bottom part is totally Panasonic, phillips screws and all. Move up, it's all GE and held together with hex bolts.
Yeah that's pretty cool. :thmbsp: Take care of the griplet issue and you'll have quite the showpiece... for those who appreciate sets for anything other than how much $$$$ they could get for them.

zeno
06-19-2017, 03:08 PM
Wasn't that chassis notorious for flyback failure? IIRC, they were $100usd, back then.
This was the start time of MANY FBT problems on most brands.
Prices were all over the place. One bottom line Hitachi 13" net
was abt $65 + shipping. Its 19" brother was ony $35, go figure.
Some brands like Zenith, RCA, Toshiba & Sony held up better but
they made up for it in spades in the 90's. And yes the FBT's went
on these cross bred GE's just like the pure Pannys.
My favorite FBT was Hitachi. To confirm it we put in a fuse & HOT
then ran it on low V. The FBT would snap some then crack open
with a big snap. Smoke & puss would pour out of it. The things we
did when bored:scratch2:
Maybe some time I will write about the GIANT elastic.........

73 Zeno:smoke:
LFOD !

Jon A.
06-19-2017, 03:24 PM
Maybe some time I will write about the GIANT elastic.........

73 Zeno:smoke:
LFOD !
Please do! I blew up a few spent capacitors fairly recently, it would be cool to learn some new things.

Findm-Keepm
06-19-2017, 03:53 PM
....Take care of the griplet issue and you'll have quite the showpiece...

This. Ain't. A. Griplet. Set.

The BC-A chassis is probably the most reliable of the late GE's - you are thinking of the AA/AB and AC chassis from the 80s. Those and the EC/EM chassis made $$ for servicers.

The later PC and PM (cousins in time with the BC-A chassis of the OP's set) also were prone to problems - with a Vertical cap (100uf/50V, C621) and a few flybacks. Nothing major like the griplet sets, and once you replaced the vertical cap (use a 100/100V), they were great sets. One 19" PC chassis set was my daily watcher for 3 years until I got a curb-crawl 20" Sony. I couldn't sell the GE - it had a pre-UL testing "red label" CRT, and was a mock-up set with no model number. It was a test bed for GE's Engineering Dept at the Portsmouth plant. I still have some of the Engineering Dept. "junque" from that haul/auction.

Findm-Keepm
06-19-2017, 04:10 PM
Here's a peek inside the 112 Channel Tuner - my 112/130 channel tuner (on the left...) is an engineering sample and probably doesn't work.

Jon A.
06-19-2017, 04:34 PM
This. Ain't. A. Griplet. Set.
Thanks for the reprimand. I wasn't the source of the information, look at this:
Uses GE tuner complete with intermitant griplets.

73 Zeno:smoke:
LFOD !

Findm-Keepm
06-19-2017, 05:42 PM
My sincerest apologies - the tuner in these doesn't have the griplets either. The white wires you see? Jumpers that solved the problem in the 112 and 130 channel tuners. (EP93X442 and EP93X590) - the earlier 108 channel ones did - they were used in the AB/AC remote/random access sets.

The BC-A chassis tuners used a Siemens design, straight from their datasheets, minus changes made for North American use. Grundig also used the same design/chipset for the prescaler and band-switching chips.

108 Channel tuners used a Toshiba or NEC chip set that was rock solid. Some folks modified them for use as tracking generators for their homebuilt spectrum analyzers. The local oscillator in the tuner was shifted, filtered and tapped for use.

One of these days, when I get a new all-in-one printer (my Canon Pixma died...) I'll scan all of the GE Engineering notes found with all of the Engineering Dept stuff. Some of it is boring - small value changes in resistors, caps and the like for performance improvement over the datasheet designs, and outright breakdowns of competitors stuff, like Sony tuners, RCA (pre-GE) tuner control modules. Other stuff is insightful - like what CRT brands and types had the best resolution with their chassis (EC and AB/AC only, nothing later...).

I think I've posted pix of bare PC-A chassis boards I have where they were checking out temperature effects on different Phenolic materials used in the boards. I've also got modules with no markings on the board, extra holes, and "ENG SAMPLE" stamped in ink on the boards. I thinned them out some - and salvaged CRT sockets, power resistors and hardware, keeping only the best 4 or 5 boards - some date back to the JA/MA/MB sets of the 70s.

radiotvnut
07-04-2017, 10:14 PM
Over the years, I've had several 13" and 17" BC chassis sets and most of them had a bad flyback. In my area, we have very hot and humid Summers and I think this is why so many flybacks and triplers failed in sets around here. I recall picking up one 17" BC chassis TV off the street and after replacing a bad power switch, it came to life - for about 15 minutes. I was test running it; and, all of a sudden, the picture got darker, fell out of sync, pulled in on the sides, and BAM - the flyback went up in smoke and stunk up my shop. When it went, it also took the HOT, voltage regulator, and both fuses with it.

Findm-Keepm
07-05-2017, 04:04 PM
Over the years, I've had several 13" and 17" BC chassis sets and most of them had a bad flyback. In my area, we have very hot and humid Summers and I think this is why so many flybacks and triplers failed in sets around here. I recall picking up one 17" BC chassis TV off the street and after replacing a bad power switch, it came to life - for about 15 minutes. I was test running it; and, all of a sudden, the picture got darker, fell out of sync, pulled in on the sides, and BAM - the flyback went up in smoke and stunk up my shop. When it went, it also took the HOT, voltage regulator, and both fuses with it.

Classic solder on the horizontal drive transformer gripe. It'd eat a flyback in an instant. The set heats up, warps the board just so, and boom - no/reduced drive, and the horiz output transistor goes into near or 100% conduction, eating the primary coil on the fly. Overcurrent protection was nil, or a small (fusible) resistor of a half-ohm or so in the B+ to the transistor collector - the fly would go, and the resistor was fine.
It was a must on these sets to resolder (with lead/tin solder) the horizontal drive transformer, the HOT connections, and check the ESR of the caps on the scan derived side - the ripple current would overheat the fly as well...

Funny thing - RCA's 2005-ish M134C chassis had the same problems....seems they never learn....:thumbsdn:

centralradio
07-05-2017, 10:14 PM
I have or had those sets here.Maybe that was the one I seen in my shed today.They had their issues.It was nice to see the insides was Japanese made then their normal rats nest of wires with unreadable crap house numbers.1980's was hot for varactor tuned tuners.

Jon A.
07-06-2017, 12:52 AM
Speaking of 1980s Japanese-made chassis, when I finally took the back off a Mitsubishi-made Electrohome I found the flimsiest chassis I've ever seen. Dusting it out somehow took out vertical sweep so I just scrapped it. Things were nice and neat in there but poorly made.

Higher-end 1980s Hitachi consoles may have been the worst of their time for complexity. Too much wiring and way too many capacitors. Even though those I had were high-end models the cabinets were junk. I thought I found a real wood panel in the base of the last one but nope, it was veneer. Why they'd disguise a panel that isn't normally visible I don't know.