Sencore VA-62A 15MHz kit, cd, etc.

[M3-SRT8]

I hear that Zenith 6S321 makes, or made, these eprom installation kits. Are they still available?

Thank you;

Lee

[Notimetolooz]

Did you send him a private message?

[M3-SRT8]

Yes. No response.

No activity since 2018.

[M3-SRT8]

Anybody know if he's still active?

[Doug]

If this mod is for thr va62 I would like to know more about it
Doug

[M3-SRT8]

Originally Posted by Doug

If this mod is for thr va62 I would like to know more about it
Doug

Yep. But, as I understand it, the eproms vary according to whether you have an early VA-62 or a later production VA-62 or VA-62A. I have the VA-62A.

[Notimetolooz]

This might get you up to speed on this Doug.
http://videokarma.org/showthread.php?t=253433
http://videokarma.org/showthread.php?t=267686


He also had one or two other threads on the kit.
Use the search on the forums here to find more threads.

I bought a kit about three years ago. I just recently used it.
Then I made a boo-boo when checking out the VA62 (some power supply issues) and blew a chip in the display. I'm still waiting to get the chip from Germany, so I'm kind of dead in the water until then.
I should have completely checked out the VA62 before making the mod.
The kit comes with a CD that contains the service info among other things.

[M3-SRT8]

Originally Posted by Notimetolooz

This might get you up to speed on this Doug.
http://videokarma.org/showthread.php?t=253433
http://videokarma.org/showthread.php?t=267686


He also had one or two other threads on the kit.
Use the search on the forums here to find more threads.

I bought a kit about three years ago. I just recently used it.
Then I made a boo-boo when checking out the VA62 (some power supply issues) and blew a chip in the display. I'm still waiting to get the chip from Germany, so I'm kind of dead in the water until then.
I should have completely checked out the VA62 before making the mod.
The kit comes with a CD that contains the service info among other things.

Ah! Thank You.

Scarey mod, that switch.

[M3-SRT8]

Originally Posted by Notimetolooz

This might get you up to speed on this Doug.
http://videokarma.org/showthread.php?t=253433
http://videokarma.org/showthread.php?t=267686
Then I made a boo-boo when checking out the VA62 (some power supply issues) and blew a chip in the display. I'm still waiting to get the chip from Germany, so I'm kind of dead in the water until then.
I should have completely checked out the VA62 before making the mod.
The kit comes with a CD that contains the service info among other things.

Power supply problems? Like a bad Lytic? Mine seem to look fine.

[Notimetolooz]

I replaced two electrolytic caps and a 5 V regulator IC. (So far.)
The big 450V cap on the supply to the Drive Amplifier (sweep drive output) was bad. If I remember right two other supplies were just out of spec. Hum and voltage level. Looking at my notes, both caps were on the main supply, the regulator was on the meter supply. There were also some resistors that looked like they had been replaced but did not match the schematic value or wattage.
This might mean someone tried to correct a problem elsewhere.
The Maintenance manual will be uploaded to BAMA shortly. It has the locations on the board to check voltages and lists the supply limits. That manual has much more in the way of tests and checks, although it looks like you need things like a vector scope for some checks.
There is a main supply board (#900) and another board for the meter and ringer supply (#1900).
Watch those board connectors!

[M3-SRT8]

Originally Posted by Notimetolooz

I replaced two electrolytic caps and a 5 V regulator IC. (So far.)
The big 450V cap on the supply to the Drive Amplifier (sweep drive output) was bad. If I remember right two other supplies were just out of spec. Hum and voltage level. Looking at my notes, both caps were on the main supply, the regulator was on the meter supply. There were also some resistors that looked like they had been replaced but did not match the schematic value or wattage.
This might mean someone tried to correct a problem elsewhere.
The Maintenance manual will be uploaded to BAMA shortly. It has the locations on the board to check voltages and lists the supply limits. That manual has much more in the way of tests and checks, although it looks like you need things like a vector scope for some checks.
There is a main supply board (#900) and another board for the meter and ringer supply (#1900).
Watch those board connectors!

My VA-62A appears to be a virgin. No repairs that I could see. All the big lytics appear to be fine, no buldging, leaking, etc.

Which DPDT Switch did Zenith specify for the mod? Can't tell from the picture.

[Notimetolooz]

Since Zenith6S321 seems to be MIA at the moment, therefore can't provide the mod kit, the best approach would be to download the EPROM data file from the earlier posted threads. Then send it to Matt's Basement Arcade to have a EPROM burned.
Website; https://mattsbasementarcade.com/
On ebay: https://www.ebay.com/itm/23267907567...gAAOSw3zNak5mR

EDIT: You will need a miniature DPDT toggle switch, for a thick (plastic) panel, like this one.
EDIT: https://www.mouser.com/ProductDetail...YPLoz4kA%3D%3D

You might find it cheaper elsewhere.
The kit included a water slide decal to label the switch, you you have to come up with your own label.
A CDROM with a lot of info was included containing the schematics, operator manual, and a Maintenance (Service) manual.
Most of that info has been uploaded to the BAMA site now.
https://bama.edebris.com/manuals/sencore/va62/

[M3-SRT8]

Thanks much. You've been a grand help. I'm piecing everything together, except for the decal, perhaps.

I was poking around inside the Sencore very carefully, pulling and reconnecting all the jumper connections and rebedding some of the ICs in an attempt to restore color output to the test patterns, but to no avail. So I contented myself with giving the interior boards a quick blow of compressed air and cleaned up the inner and outer surfaces of the cabinet. That's all I dare do.

I won't be able to get to it for a few days as I am training a new horse in dressage.

No-Time Tolouse...!

[Notimetolooz]

Right!
The Maintenance manual isn't really a troubleshooting guide but it has performance checks and adjustments. With the schematics it should be possible to trace the signals with the aid of a scope and of course a meter.
From what I've noticed it is pretty involved with signals going through other boards you might not think are involved.

[Notimetolooz]

A "Simplified Guide" has been uploaded to the BAMA site.
It is entitled to be about the VA62A but it fits the VA62 also.
Seems to be intended to be use with a later model RCA TV that has SAW filters instead of the adjustable IF transformers/filters.
https://bama.edebris.com/manuals/sencore/va62/