Broken VT510

Tom Hunter ccth6600 at
Sun Jul 26 02:22:29 CDT 2020

Hi Paul,

These are generic Taiwanese terminals with a DEC badge. They were made by
"ADDS" - later renamed to "Boundless Technologies". Both IBM and DEC got
their low-end terminals manufactured by them. Once you open it you will
probably find the actual manufacturer's name on the PCB and then you could
try to find the schematic.

There is a good chance for a tube transplant to work. Most 14" magnetically
deflected CRTs have very similar specs except for the tube pin-out. If you
can't find a datasheet for the two CRTs, then you can still identify the
pin functions just by carefully looking at the tube neck. The anode
voltages for 14" CRTs are all in the same range about 12 - 15 kV.

The yokes too would be very similar so likely the VT510 tube with it's
original yoke would work fine in the "screen fungus" VR201 terminal.
Alternatively you could swap over the yoke from the VR201 but likely that
would require more adjustments then just keeping the yoke already on the

Finally you could just buy a working terminal on Ebay for relatively little
money.    :-)
Here is one example:
The "Buy it now" price is $250 but it has a "Make offer" button so try $100
or $150.

The VT510 was under $500 when new.

Tom Hunter

On Sun, Jul 26, 2020 at 2:36 AM Paul Koning via cctalk <
cctalk at> wrote:

> I recently brought home a VT510 that has been sitting in my office,
> rescued from a lab from way back when it was a DEC office (ZKO).
> Unfortunately, when I plug it in and push the power switch, nothing happens.
> Rather than just open it up and poke, I was hoping others here might have
> some experience with that model.  Are the schematics anywhere?  Not on
> Bitsavers as far as I can see.  Are other terminals at all similar?  The
> newest schematic I see is for the VT340.
> It would be nice to get the terminal working again.  Alternatively, a wild
> idea would be to use the CRT in place of the "screen fungus" infested VR201
> CRT I would like to repair.  Any chance of that working?
>         paul

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