problem in HP 3000 System 37

[Iban Cardona]

Hi,

some weeks ago I've  purchased a System 37 in ebay. This unit was ebay in
the year 2020 and the owner was made this video too:
https://www.youtube.com/watch?v=F1CZKQtaoSo

When I power up the displays shows a 1. Sometimes if I stop and start fast
the display shows a 2, but in all the cases all the leds stills lighted.

The voltages on the power supply are OK, and in general I the unit have a
good look, I don't see corrosion or leakages from capacitors.

Looking the SPU training PDF of Bitsavers/HPMuseum , looks that maybe is
related with a ROM or the WCS.

Somebody have more info about this error, or know if is possible get some
schematics / service manual?

Thanks a lot

Iban