HP-65 1333A18516 - [SOLVED] request for advice

[albertofenini]

(06-15-2024 07:25 PM)albertofenini Wrote:  

(06-15-2024 05:35 AM)teenix Wrote:  Pin 8 of the cathode driver is the Reset Pin (1820-1226)
Pin 9 is the STEP IN pin from the anode driver.

Pin 6 of the Anode driver is the STEP OUT pin to cathode driver. (1820-1029)

Both pulses are on page 12 of the Classic Notes.

I'd make sure these pulses are there, and if not check the traces back to the board.

The RCD pin from the CPU board is the left-most interconnect pin to the keyboard.

You might like to check the ABCDE lines to the anode driver as well, The signals image on page 10 of the Classic notes.

Other end of interconnector, right side pins counting left, 1 2 3 6 and 7. Pins 1 2 3 4 and 5 on anode driver.

cheers

Tony

Hi Tony

before take any signal with the scope we checked the voltages
(please note that the card reader was not connected)

Vbatt is 3,8
Vbsw @ the logic board (pin 12) is 3,8

1820-1226 Cathode Driver
Vbsw @pin 4 : 0 V
Vcc @pin 10 : 1 V
Vbsw @ pin 15 : 0 V

1820-1029 Anode Driver
Vbsw @ pin 11 : 7 V

1810-0147
Vbsw : 3,8 V

1810-0146
Vbsw 3,8 V


We have also found three traces that looked like had been cut
but continuity has been verified (you can find them in the updated gallery)

However withe ICs and LDEs and Inductances mounted
is pretty hard to check more traces

Thanks for the support !!



Updated gallery :
HP-65 1333A18516

Tony forget the previous post as the measurements were probably mistaken

we have measured the voltages from both a working HP-65 (S/N 1508A04995) and
the HP-65 under repair S/N 1333A18516

We have measured with the scope all the suggested curves for both units and both
at the logic board interconnects and at the drivers, I'm posting two links to the images

Please, keep in mind that the logic board S/N 1333A18516 connected to the
keyboard with the drivers from the 150804995 works perfectly

Let us know what do you think
thanks again and take care !!

Curves from 1333A18516 can be seen here :CURVES FOR NOT WORKING S/N 1333A18516

Curves from 1508A04995 can be seen here :CURVES FOR THE WORKING S/N 1508A04995