tl866 can't see 27c4096

[dragmar]

Has anyone managed to program the epprom 27c4096 with the TL866 programmer?

I have a PLCC44 to 40 adapter in which I made changes with user suggestions in this forum.
But TL866 still can't see epproms?

What else do you need to do?

[terriblefire]

Yeah i could never get that to work. Hence my hatred of PLCC 44 pin roms.

TL866-II does not help either

04FFC045-088E-47BD-9C82-A05F2B479C70.jpeg

[derkom]

Your modifications don't look right to me... Can't swear, since we seem to have a different socket layout there, but it seems off.

IMG_20200617_184159.jpg

[DoG]

I have made the two small solder bridges necessary and it worked fine with TL866.

Get one of these instead.

[JezC]

I think @rubber_jonnie did a mod to his adaptor & I copied his to get mine working...the thread is below
https://www.exxosforum.co.uk/forum/viewt ... lcc#p20619

HTH - he sent me an even clearer picture of the underneath if needed...but can't find that one quite so easily :roll:

[Tomswork]

Yes the programer works well with the 27c4096 you need the socket wired for it rather than the pic

Tom

[rubber_jonnie]

This is mine, pin 1 of the PLCC socket is at the top:

IMG_20200606_115449__01.jpg

If you're not seeing the ROMS then there are a few possibilities:

1. The ROM is not making a good connection in the socket, because the socket is bad.

2. The ROM is not making a good connection in the socket, because the ROM pins aren't right. EPROMS are particularly bad for this if ceramic, as the legs have no stabilising 'gutter' to hold the pins in place round the bottom of the chip.

3. The adapter has more disconnected pins than you know about.

You can check the ROM pins easy enough under a magnifying glass and make sure the pins are all in a good position and not touching. You should really check more than one ROM just in case.

For the adapter, if the socket is bad (I think this unlikely) then buy a new adapter as suggested by DoG.

If you think the socket is fine, then the best suggestion I can make is to get a PLCC 44 pinout and work round from pin 1 to pin 44 of the adapter and continuity check the whole socket and mark what is and isn't connected. I did this and got mine working once I realised what wasn't connected that should be.

If after that it still doesn't work, then it's back to DoGs suggestion again and buy a new one.

[dragmar]

This morning I received a new, different PLCC44 adapter is DIP40. It's a universal adapter (epprom / MCU) to choose from

He also disappoints me !!
The programmer has no problems with other systems and I have many, but epprom PLCC44 cannot see.
The seller assured that there should be no problem.
Do they even check these adapters !!

@rubber_jonnie
can you show the top of the adapter you've reworked?

[rubber_jonnie]

@dragmar Firstly, I don't think a pic of the top of my adapter will help, there is no rework to see, it's all in the other picture.

The one thing that did spring to mind is that you're selecting the correct brand of 27C4096 chip from the list, because that can make a difference. For some brands there are different chip variations too, you must select the correct one.

Also, if your programmer specifies a PLCC version of that chip (Mine doesn't and it's a TL866II+) don't select that, select the 40 pin DIP version.

The thing you really need to check is that the pins on the DIP part of the adapter go to the correct corresponding pins on the PLCC socket, which you can do with a multimeter. Until you have verified all the pins are connected as they should be then you're going nowhere.

Download a datasheet for the 27C4096, it will have the pinouts for the 40 pin DIP and PLCC packages. Then, on the adapter, work through each pin on the DIP and PLCC and using a multimeter, buzz out each pin pair to make sure that every pin from the DIP matches the corresponding pin on the PLCC socket. It really is the only way to be sure that the adapter is wired as expected.

Note that on the PLCC adapter, pins 1, 13, 23 & 33 have no corresponding pin on the 40 pin DIP chip, so you can ignore these.

[dragmar]

@rubber_jonnie

it was a photo of my conversion adapter.

But you are right, it turns out that I will have a few adapters from local sellers guaranteeing their operation in TL866 and none of them will work !!