This is not intended to be a comprehensive guide (at least not yet), but rather to address some very common issues seen on the 1T-TBC type Cypress TBCs. That includes both early-, mid-, and late-gen models.
Early-gen
Early 1T-TBC are almost identical to early green AVT-8710 -- meaning excellent. But only when properly working, of course. Now that where this guide comes in. Sometimes the good 1T-TBC can appear to be not-good on initial usage/testing.
This is a common visual issue when first turned on:
1ttbc-usage-rainbows.jpg
This generally causes people to freak out, especially given the costs of TBCs. But it's rarely the visual presentation of an actual problem. TBCs are analog signal processing devices, and all of them require lock time to find the signal. Some take seconds, other take a portion of a second. Some can even mis-lock, which is what this is.
Now, on some TBCs, mis-locking is a PITA, requiring resets and babying. But the 1T-TBC signal reset is simple: just cycle the format (system, "SYS"), generally using the down arrow. Sometimes the up arrow, but usually the down arrow. (Why? No idea. I'm guessing it doesn't like the NTSC > NTSC 4 jump.)
See attached clip
1ttbc-usage-cycling.mp4 (3.63 MB) at end of post.
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Easy!
However, do note that failure to lock can be an early sign of the dreaded Cypress "attitude problem", where chips are suffering slow heat death. This is why customizing with heat sinks has become so important in recent years, to stave that off for more years. While some people have had luck simply replacing caps, other have had to replace board chips. Some TBCs just eventually failed, DOA, too much (ab)use and overheating. But I hope this isn't your situation.
Mid-gen
Necessary history lesson
Mid-gen units are somewhat rare. Not a lot of Cypress TBCs were produced during that time, mostly 08-09.
It's widely known that
green AVT-8710 is (usually) good, while
black AVT-8710 is (usually) bad. And again, 1T-TBC is essentially metal-cased AVT-8710s.
I say "usually" because
green>black wasn't a clean break. That's because the TBC quality change had nothing to do with color, and everything to do with chip availability (as mostly caused by the GFC, aka the '08-09 recession). Cypress began to run out of chips, and substitutions were made. Eventually, so much was substituted, that it really didn't act like an AVT-8710 anymore. Somewhere in the middle of that changeover (~2010) the cases also changed, probably for the same supplier reasoning. So some green AVT-8710, and some black AVT-8710, are from the mid-gen era. The chips/firmware had changed enough to make it imperfect, but not enough to make it flawed performance.
However, unlike AVT-8710, 1T-TBC were always black metal cases. There's no easy external tell. In fact, there's rarely an easy internal tell either. The performance of the TBC must be analyzed.
For 10+ years now, the easy tell for good/green early-gen Cypress, and black/bad late-gen Cypress -- and wholly ignoring the mid-gen -- is the "JVC menu test". JVC S-VHS VCR menus (and blue screen) are generated video, and that seems to aggravate the mid/late units. But it's an inconclusive test, not distinguishing between mid- and late-gen.
Late-gen Cypress are infamous for multiple possible issues: frame sticking, pixel noise locking, and the aforementioned menu rejection. Whereas mid-gen can vary, from "excellent video, weird menus" to having other performance issues.
Bad startup, but good unit
Mid-gen 1T-TBC units are easy to confuse with late-gen (bad) units.
** So don't use this information to try and quickly determine if yours is mid or late -- you'll probably be wrong. It's taken me years to develop testing criteria, involving multiple capture cards, multiple VCRs, and in multiple formats -- something that 99.9%+ of others do not have the ability to recreate.
Both mid and late tend to start with stuck menu corruption on screen. Like so:
1ttbc-usage-cycle.jpg
But here's the difference: Press PLAY on the JVC VCR, and then press STOP about 1s later.
- In general (not always), the mid-gen unit will (sort of) right itself. You'll be greeted by a bluescreen that looks like it has 8-bit NES (Nintendo) scan lines (because only 1 field has the video), but otherwise flawless.
- The late-gen tends to just resume having corrupt images.
The real test comes next (usually).
- When you enter the second page of a JVC menu, the text tends to overlap unreadable.
- But on the mid-gens, the menu is normally just "8-bit scan line" in appearance. It's fully readable, usuable. No sticking, no overlapping text.
Note that the channel number (F-1, L-1, or a #) does always overlap in the corner.
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See attached clip
1ttbc-midgen-menus.mp4 (2.68 MB) at end of post.
Late-gen
Late-gen 1T-TBC are the most common unit you'll find. This is why random buying TBCs can be a terrible idea. I'd estimate that probably 80% of all 1T-TBC found "in the wild" in the 2020s will be these unwanted problem units.
I may cover these units more later, but honestly, what's the point? Bad unit bad. No amount of troubleshooting or usage notes will ever overcome this.
All generations
At this late date, most units long ago were separate from the OEM power supplies. Most of those weren't great anyway, and the PSUs also heavily varied over the years. So most people now attempt to shove any AC adapter into the unit, not realizing the issues.
Sometimes, even a PSU from another 1T-TBC generations can reject the unit! All Cypress TBCs tend to be really finicky with the power supplies.
For example, this is what happens on a good early-gen 1T-TBC, using a power supply that works flawlessly with both mid- and late-gen units.
1ttbc-midlate-badoutput.jpg
Noise spew is a known issue of late gen, but a bad PSU can cause it too.
