TL866II pls159 programming (to repair Tektronix 2710) - Page 1
Forum section: electronics / repair

author: grumss
author_rank: Contributor
timestamp: November 15, 2020, 12:22:40 am
content: Hello everyone,I am in the midst of trying to repair my Tektronix 2710, I have found "JED" files to reprogram the PLS159 chip...Am i able to program PLS159 chips on my TL866II programmer? How would i go about it? (the software doesnt seem to list the chip)..I am really "green" when it comes to chip programming, very much appreciate some help from you guysAs a bit of history-"My screen also has gone into the dreaded displaying garbage symptoms. After spending a lot of frustrating time playing around i think i can put my finger on the problem (mine anyway), digital is certainly not one of my strong points but here goes..It seems the SA's display pages are changed by pin 7 of U260 (PLS159), this chip is supposed to send a negative pulse to a binary counter (U326). The binary counter counts until the correct page/s is displayed then is suppose to stop.The binary counter also sends signals to other chips including U308 which controls blanking and "dotenable"! (one of the classic things we all see with the fault)...What seems to be happening (in mine anyway) is that U260's pin 7 is caught in a near mid state, around 4V in mine- any noise in the circuit is +- on the 4v and sending the page select counter into near constant counting- this seems to be why we see all of these unusual displays....Now to prove the point, i pulled the pin 7 output up to 5v with a high value resistor- the SA now always boots to a spectrum display which i assume must be default with the initial (000?) binary output from the counter.. no other screen data is displayed but at least i can see a working spectrum..I experimented with mosfet switching on pin7 to lighten its load but had no success.. I dont think it pulls down at all...Now all i have to do is find a PLS159, the code and try to program it! GEEZ!! (id very very thankful if one of you guys can help)I dont think the PLS is doing very much looking at its clock, but for me the code would be very difficult to invent.."

author: giosif
author_rank: Frequent Contributor
timestamp: November 15, 2020, 12:19:30 pm
content: Hi (again),I have a programmer which is capable of programming Philips/Signetics devices, including PLS159, so I could do that for you, if you send me your chips.That said, I am picking up on your wording - "... reprogram ..." - as far as I could investigate, the PLS ICs are programmed only once and cannot be reprogrammed.So, unless you are looking to program new PLS159 ICs, I don't think anyone can help you.I would be glad to be contradicted on this, as I am in the same situation, where I am trying to fix a display board with 5 bad PLS ICs.As far as I could research, it seems the GAL chips were like the PAL/PLS ICs, but re-programmable.But whether there is a PLS159 GAL equivalent, I don't know.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 15, 2020, 03:45:01 pm
content: Wich programmer ?The datasheet do say "field programmable" but the pls159A is an enhanced version of the 159 and do not use the same algorythmYou have NXP, Signetics, Philips as brandsome STAG programmer can do themsome Elnec programmers too

author: giosif
author_rank: Frequent Contributor
timestamp: November 15, 2020, 05:00:40 pm
content: My programmer is a HI-LO System ALL-11P2.

author: up8051
author_rank: Frequent Contributor
timestamp: November 15, 2020, 06:44:00 pm
content: I have old Labtool-48, it support PLS159 & PLS159A.PLS159AA (PLCC case) are avaliable at ebay (It's is a Polish seller, so local for me).An option may be replase PLS with GAL but nfortunately I do not know any program to convert JED files to equations handling PLS1xx chips,conversion from PLS to GAL can be difficult or impssible.Are you sure you have the correct JDC file?

author: giosif
author_rank: Frequent Contributor
timestamp: November 15, 2020, 11:35:51 pm
content: Well, according to this web article:https://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_other/2710.htmland Google Translate, it seems someone has managed to replace a PLS155 with a GAL22V10D.The content on that page is way over my head, but I guess this means the PLS159 could also be replaced with a GAL device?

author: shakalnokturn
author_rank: Super Contributor
timestamp: November 16, 2020, 12:14:04 am
content: I didn't go to the trouble of translating and reading the full German page but it does look like he re-wrote the logic for the GAL22V10D after doing logic analysis on the (partly?) defective PLS155. That should also be possible for a PLS159, the other option if timing isn't too critical is getting it done with an MCU. The GAL22V10 although handy in such cases and still quite available are also obsolete now.In any case for OP it means more bother than wanted.

author: grumss
author_rank: Contributor
timestamp: November 16, 2020, 07:12:43 am
content: Hello again giosif,Thankyou very kindly for your nice offer... Yes i think I would be very smart to send them to you if you dont mind.I have 4 pls159 chips coming from Poland? (Thank you for pointing that listing out to me previously)Being a one-time program chip i shouldn't be messing around (not a good chip to learn on)....I obtained the hex code from herehttp://www.ko4bb.com/getsimple/index.php?id=manuals&dir=Tektronix/Tektronix_-_2710_Spectrum_Analyzerfor those of you that need it.I expect the chips to take a few weeks to arrive, i will send you (giosif) a message when i receive them... Thanks heaps- hope i can exchange the favor

author: giosif
author_rank: Frequent Contributor
timestamp: November 16, 2020, 05:32:01 pm
content: Hi,Sure, no problem.Just let me know when you receive them.For the code, I am guessing you mean the .JED file, correct?