HP-67 1805S02334
|
03-21-2021, 09:42 PM
Post: #3
|
|||
|
|||
RE: HP-67 1805S02334
The Faceplate
Hi Everyone, not much to say on the faceplate, keys and faceplate have been washed but it will be necessary to spray the TS80 to bring it back to the original aspect, that will be done as the last thing The Card Reader The card reader has been completely stripped of all the components this is one of that latest version, it can be taken out without de-soldering thanks to the pins Cleaned with the usual mixture, two traces needed to be restored and they are the Motor and the RB traces The wheel has been restored with two o-ring and the clutch has not been done has it keeps (for the moment) a good strength It has been mechanically tested and a card goes thru regularly However, sad to be said, it doesn't work ... The problem seems to be in the RA and RB channels, though we have not tested the writing feature for the moment Both RA and RB are noisy once the calculator is powered on, even if the card reader is inactive. When disconnected from the logic board it looks ok, also RA and RB on the logic board are ok when the card reader is not connected We have put this logic board in a working unit and it can read just fine, so we presume the card reader controller on the logic board is fine We changed the amplifier on the card reader with a known good one and it behaves like this. When a card is passing thru you can see the correct wave in between the noise Please be aware timing has been set differently when it was not reading vs when it was. Also, keep in mind that on the keyboard pcb the two traces that have been repaired are SB and SC We could not test the impedance, but we have measured the resistance and it is : between red and yellow : 44 ohm between blu and orange : 43,6 ohm these values are comparable with values measured on other magnetic heads As always, any suggestion is very welcome ! Take care !! Updated album : HP-67 1805S02334 Edoardo & Alberto |
|||
« Next Oldest | Next Newest »
|
Messages In This Thread |
HP-67 1805S02334 - albertofenini - 03-20-2021, 11:08 PM
RE: HP-67 1805S02334 - teenix - 03-21-2021, 01:38 AM
RE: HP-67 1805S02334 - albertofenini - 03-21-2021 09:42 PM
|
User(s) browsing this thread: 1 Guest(s)