Wyse terminals using same hardware.

Previously on this channel...... On Sun, 18 Feb 2007, David Griffith wrote: here has what many to Whoops. They're not identical. I've unearthed a Wyse 99gt with bad screenburn and nasty case discoloration. Seems close enough for my purposes. <<<<< Yes, Wyse made some terminals that WERE the same, just different PROMS. The Wyse-75 and Wyse-50 were the SAME hardware. You can convert a Wyse 50 (weird escape sequences) to a Wyse-75 (nice VT-100 type escape sequences) with a bit of work. I've done it very successfully (it was a few years ago, in a previous life). Steps: 1) Have a Wyse 75 nearby that can be "borrowed". You will return it in its original condition. 2) Have the Wyse 50 (soon to be a Wyse 75) around as well. 3) Get a couple of EPROMS that are the same as the ones inside the Wyse 50/75. At the moment I don't remember, but a pair of 2764's sounds familiar. 4) Open up the Wy-75's logic board and get access to the nice socketed prom chips. 5) Mark the chips and their sockets to make sure you don't fudge them in the wrong place. 6) Make copies of these chips in your EPROMS. Be aware that if you don't have high enough speed chips, the unit you are "modding" might NOT work in 132 column mode. 7) Place these chips in the Wy-50's board where they came from the WY-75. 8) (Here it gets a bit tricky!) Remove the EEPROM (it is a 16 pin chip and socketed) from the Wy-75 and put it in the Wy-50's socket. Save the Wy-50's EEPROM for a step further down. 9) Power up the Wy-50 (now a Wy-75) and get into the setup menu. Note that the keytops are in a few different places, but since you have a Wy-75, just make legends for that copy the keycaps. 10) With power ON (careful now) gently remove the EEPROM chip inserted in step 8. 11) With the power STILL on insert (careful now) the EEPROM chip from the original WY-50 back into the socket. 12) Since you are in the setup menu, do a "save". This saves the Wy-75 stuff into the EEPROM and makes sure that bits are set to allow the Wy-75 to work. If you DON'T do this, the terminal WON'T power up in a useful state AT ALL! 13) Put the original Wy-75 parts back into the "donor" wy-75 and re-assemble it. They won't notice ANY difference as you haven't changed anything! 14) Re-assemble the former Wy-50 (now a nice functional Wy-75) and add some labels to the keyboard for the keys that are different from the Wy-75 (there are a few). 15) Be happy. You just upgraded your Wy-50 to a Wy-75. Enjoy the nice VT-100 style escape codes. Note that some of the "F keys" (F1-F6 as I remember) have specific functions and are NOT programmable. So, there you go. Yes it is the same hardware. The Wyse 75 firmware looks in the EEPROM to see that you started out that way, and wedges if not. This is the reason for the dance shown above. I tried it without the EEPROM dance and it DID NOT work. Then I figured it out. I didn't have an EEPROM (2401??) programmer, so I couldn't clone that part, but since the above works (be very very careful), it shouldn't be a problem. As the saying goes: "West and Welaxation at Wast ha ha ha ha..." (insert Elmer Fudd voice here). -- Tom Watson Generic Signature t_wtom at qualcomm.com (I'm at work now)