Old counter chips. Need replacement. Urgent. 1

[Skogsgurra]

Hi,

I'm in a real pinch here. Printing press with old counter chips. I think Teledyne/Chrystalonics, Type 374AL/CL.

Are there any replacements? Or do they still exist. A sudden answer is appreciated.

 

[richs]

Hi-

Are you sure that it's a counter and not a octal latch?

If it does turn out to be an octal latch, you MIGHT
try replacing it with a 74LS374. Please watch fanout/fanin
as the LS parts have twice the input requirements from
the L series part. You might also look into the BI-CMOS
versions, however, there are pull up requirements that
might make it more cumbersome than just swapping in
'LS parts.

Best of luck!

Cheers,

Rich S.

 

[Skogsgurra]

Thanks rich.

Yes it is a counter. There are three of them that ramp the speed set-point up and down. The output from the counters are fed to an old D/A and the analogue setpoint is taken from there. We have found the defective chip and are trying to rearrange the circuit to circumvent that defective chip. We will get a somewhat lower resolution, but that seems to acceptable to the printers.

The 374 is not preceded by any letters or numbers - this seems to be one of those slow speed high level devices that were used before CMOS 4000 series took over that niche.

The question is still open: is there any equivalent or replacement? I have tried Siemens and Telefunken LSL families, but they do not have bidirectional counters. Motorola perhaps, but I haven't contacted them (=found the right person) yet.

 

[cbarn24050]

Hi, if it's 5 volt then you could program a PIC, a trivial programming problem.

 

[Skogsgurra]

Right,

We brought out the good old PicMaster and a 16C57. But before we had figured out how much interfacing we needed to work with the 12 V signals, we found that the 0.1 percent resolution wasn't needed. So we crippled the counter and are now running eight bits. That seems to be OK with the printers. All is well and the press is spewing out magazines again.

But, of course, we still need a replacement.

Thanks for your efforts!

 

[cbarn24050]

Hi, I had a feeling it was 12v. Interfaceing shouldn't be too bad, a bit bulky maybe.

 

[DougMc1054]

Try using TSC374AL Counter by Microsemi

 

[Skogsgurra]

Thanks Doug,

That seems to be exactly what we need. Thanks a lot

Do you know any Scandinavian distributors? Or European.

 

[DougMc1054]

I dont see anything listed.
IC brokers for Europe

http://www.doom.com/

http://www.dialelec.com/266.html

 

[nbucska]

If it is such old circuit, it can fail any time again.
If you know what it is supposed to do, it may be simpler
to redesign it with modern IC-s.


<nbucska@pcperipherals DOT com> subj: eng-tips

 

[Kostasp]

Skogsgurra hi, is it by any chance your press a Harris (Marinoni). If yes, this problem was causing the speed to increase decrease at certain times.
Thanx

 

[Skogsgurra]

Yes Kostasp, you are right! It is a Harris press. The counters are in the ramp generator. One is defective. Do you happen to know how to find a replacement? Or do you have one 374AL/CL that you can sell?

 

[Kostasp]

i wish i had but i am on search as well. At the moment i have a problem with press speed. Especially in the morning the speed in not constant (increasing decreasing) and not all the time. I would apreciate any sugestion.
Thanx

 

[Skogsgurra]

Sorry to hear that, Kostasp.

It could be the D/A chip. It is an old Analog Devices chip, the one with a golden lid. It is a current source D/A and feeds a 560 ohms resistor, so the output signal is quite low. It is then amplified in an opamp with rather high gain.

If the speed is varying in the morning (before the heat has built up in the cabinet, I would suspect either the opamp itself (it is usually socketed and easy to change) or the potentiometer in the feedback. Small variations in the potentiometer division ratio can make the output change quite a lot.

These presses are getting quite old and the electrical cabinets are usually placed close to them. I have had cases where the printing ink and paper dust has aggregated on the PCB and made operation unstable. Have you tried to clean both sides with alcohol? It does help in many cases.

Or shall we join forces and program a micro to do the job? Make a little mezzanine board that plugs into the three sockets and contains micro and 12 V interfacing?

 

[nbucska]

I think it would be simpler to replace the whole board
with a new design. Do you know the input signals/sensors and the required outputs? Do you have schematics or can you
get one ?

If it is so old, it must be two layer PCB -- it should be easy to trace out the schematics. It may be harder to find the data of the old IC-s.




<nbucska@pcperipherals DOT com> subj: eng-tips

 

[Kostasp]

I dont know if it would worth the efort to develop a board since is such an old machine that i think her time is limited. Most of our machines are already replaced with new KBA machines. Not that those are similar quality but their technology is closer to my knowledge.
Also i am missing quite a few drawings from the Harris since it was bought second hand quite a few years ago that i was still a student in UK.
Whatever drawings i have i ve also made them in electronic form so if you intrested i can send you a copy of the cd.

 

[Skogsgurra]

Kostasp,

I think so too. I have actually recommended the customer to install modern equipment on that machine. But before this happens, it needs to be kept running for a year or so. The 10 bit to 8 bit conversion seems to work quite well. I think we should leave it so.

Interesting that you have the drawings in electronic format. As you know, we are not supposed to reveal mail addresses here. But a fax number is OK, I think. So, here it is: +46 586 12316. Fax me your mail address and I mail you mine.

 

[nbucska]

Skogs:
There nothing in the rules about mail,E-mail, phone etc.
but if you post your URL, use non-machine readable format
-- see mine.


<nbucska@pcperipherals DOT com> subj: eng-tips

 

[Kostasp]

skogsgurra

I have send you a fax with my details. feel free to mail me any time.