troubles with the CBM 3022 printer

[daver2]

It should be possible to make a NOP generator for the 6504 CPU. I am sure we did something similar for a CPU in a Commodore disk drive at one point...

Dave

 

[Hugo Holden]

There are some interesting quirks involving using a 2732 to replace a 2332. One of them is that the 2332 came with mask programmable chip selects, at least Rockwell ones did, a company would specify how they wanted it when they ordered the chip. So that if you come across a 2332 in some machine, these may be different to one in another machine. Also Rockwell made two versions of the 2332 to complicate things as well. In any case , looking at the schematic that the particular 2332 is in, it is usually easy to see how the chip select system was organized and then the adapter can be made to suit that. I have attached a page from an article I did on the RM65 video card, when I was confronted with the same problem. Also it is actually easier to use a 2532 to replace a 2332 than a 2732.

 

[giobbi]

the strange part is that even when the printer starts working (i.e. self test) it hangs after about one page and half. I searched through the reset line and it seems to me it's done using a capacitor. The reset line it's also connected to the 555 pin#4 (reset).
I think that it costs nothing to change the capacitor, I will try that and see what happens....

Apparently my adapter doesn't work... this is how I've built it. Can you confirm me it's ok?

 

[giobbi]

There are some interesting quirks involving using a 2732 to replace a 2332. One of them is that the 2332 came with mask programmable chip selects, at least Rockwell ones did, a company would specify how they wanted it when they ordered the chip. So that if you come across a 2332 in some machine, these may be different to one in another machine. Also Rockwell made two versions of the 2332 to complicate things as well. In any case , looking at the schematic that the particular 2332 is in, it is usually easy to see how the chip select system was organized and then the adapter can be made to suit that. I have attached a page from an article I did on the RM65 video card, when I was confronted with the same problem. Also it is actually easier to use a 2532 to replace a 2332 than a 2732.

Yes, in example the 2732->2332 character generator adapters for C=64 and VIC-20 are different from the 2732->2332 PET adapter (iirc the adapter for the VIC-20 is also different from the C=64 one).
So now I'm quite confused, because I don't know how to make a 2732->2332 adapter for the printer LOL
About the 2532 vs. 2732... you're right, but the 2532 is hard to find and quite expensive, and my programmer doesn't program them without an adapter... and I have a lot of 2732 too, so in my case it's easier to use a 2732.

 

[daver2]

Shouldn't you be using CS2 (the active HIGH chip select) from the 2332 socket and wiring that to the input of the inverter?

It becomes inverted (to become an active LOW signal) and you feed that into the active LOW /CE pin of the 2732 EPROM.

You appear to have correctly connected the /OE pin of the 2732 EPROM permanently to 0V.

Dave

 

[giobbi]

Shouldn't you be using CS2 (the active HIGH chip select) from the 2332 socket and wiring that to the input of the inverter?

It becomes inverted (to become an active LOW signal) and you feed that into the active LOW /CE pin of the 2732 EPROM.

Do you mean I should connect the socket pin #21 (instead of pin #20) to the 74LS04 pin #9, and leave the /CS1 not connected ?

I used /CS1 because the original 2732 -> 2332 adapter for the PET machines by Ray Carslen connected /CS1 to /CE. So I just drop an inverter in the middle.

 

[daver2]

Yes, but look at the schematic for the printer to see how the original 2332 ROM is wired.

It is no good copying someone else's work if this ROM is wired differently!

Dave

 

[giobbi]

Yes, but look at the schematic for the printer to see how the original 2332 ROM is wired.

It is no good copying someone else's work if this ROM is wired differently!

You're right. But I would never think to look at that if you didn't tell me (I have not enough knowledge for that, unfortunately... but I'm learning LOL)
However the adapter works fine now, and also the printer seems to be OK, I was able to print 6 pages of self test and it didn't stop anymore so maybe the problem was the ROM, actually.
I need to put everything together and connect it to the PET and see if it works. This is the next step, I will tell you later

EDIT: the damned thing just worked fine until I put everything together and then stopped to work again

 

[daver2]

According to the schematic, pin 21 of the 2332 socket (CE2) should be connected to the input of the inverter.

Pin 20 (/CS1) of the 2332 is permanently connected to 0V and is not required to be connected to the 2732 EPROM.

Dave

 

[Hugo Holden]

Yes, in example the 2732->2332 character generator adapters for C=64 and VIC-20 are different from the 2732->2332 PET adapter (iirc the adapter for the VIC-20 is also different from the C=64 one).
So now I'm quite confused, because I don't know how to make a 2732->2332 adapter for the printer LOL
About the 2532 vs. 2732... you're right, but the 2532 is hard to find and quite expensive, and my programmer doesn't program them without an adapter... and I have a lot of 2732 too, so in my case it's easier to use a 2732.

I much prefer to use the 2532 than 2732's with adapters, because the 2532 suits the PET. Also other projects where there were once 2332's.

The 2532 is not hard to find or expensive in some cases (there are 124 listings for them on ebay), you just have to look a little more through them. If you are buying any, my advice is go for NOS ones with the large sized dies. I have bought these before from this American seller, they are not expensive at $7.95, but it looks like other people know and are buying them out now, so you might have to be quick to get a bargain for excellent parts:

TMS2532JL-45 Texas Instruments 32K EPROM - UV Eraseable | eBay

Find many great new & used options and get the best deals for TMS2532JL-45 Texas Instruments 32K EPROM - UV Eraseable at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Also, the common and economical GQ-4x programmer does the 2532. Avoid any 2532A's these have a lower programming voltage, you can still do them on the GQ-4x, but, the chips themselves are more problematic, they also have had a number of issues with these in the pinball & video game industry.

Avoid "refurbished parts" they have a moderate dud rate and you don't know what thermal or electrical traumas they have been subjected to in the past. NOS stock is always a safer bet, but not often as economical though.