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Need help with "unresponsive" Teletek FDC-1C all in one computer-on-a-board.

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USASAgencyman

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Need help with "unresponsive" Teletek FDC-1C all in one computer-on-a-board.

I've already e-mailed Arthur S., but thought this can't hurt. My Q&T turned out to be just a branded case, the "CPU board" turned out to be this Teletek FDC-1C, and I cannot wake it up.

I am hopeful it is my own ignorance keeping me from getting some response from it.

Power supply was tested component by component, and then the wiring, drives and motherboard were all checked out for proper voltages, floppies are Qume DataTrack 842 and they both turn smoothly if somewhat noisily, main AC motors. There was a Compupro RAM 17 installed as part of the deal, but I took it out in case there was an interrupt situation. This board is supposed to at least boot with its minimal on-board RAM.

Monitor, a VT-520, with an old PC keyboard, is fed from J1, a 20 pin header to D-25 connector on Ser.1 Floppies have the wide ribbon 50 pin header > to edge connectors on drives.

I've been through the monitor setup and tried several different combinations, but so far the CPU does not hear me or refuses to speak back. The only thing that happens when I twist the ignition key is a single variable special character, letter on the monitor, and a backward question mark when going off. I assume this is just the monitor seeing some voltage.

Ideas?
T.I.A. for any input, including noob-bashing, if it is even the least bit educational!

Bruce Hinton
 
patscc said:
Herb Johnson seems to have some documentation available here http://retrotechnology.com/herbs_stuff/d_teletek.html
Don't know if you've tried him or not.
patscc
Click to expand...

Sorry, forgot to mention, I've already bought all that! Most is over my head at this point but I am willing to learn, if I find the first evidence of intelligent life's tinkering in the card, some output or complaint. And I have to be able to do that "Command" thing! :)

Thanks for the reply,
B.
 
I am not solely looking for some free magical advice; I am quite willing to pay a service fee to anyone with the means to test the card, so if any here have so much as heard a rumor of about a person who can do this...

So far the drives spin, but no head movement is evident, I don't think a boot disk is a useful item yet. It only hurts when I think... :)

B.
 
My only experience with Teletek was with the Systemaster setups (multiple CPU boards). However, Teletek always crammed a lot of circuitry on their boards and tended to load the onboard regulators pretty heavily, so I'd start by checking to see if the regulated voltages on-board were up to snuff. Another thing that was very common for the time was for the RS-232C level translator chips to get zapped by static electricity, so I"d replace them also.

I'm assuming that your teminal is set up with the right speed, data bits, etc.
 
Chuck(G) said:
My only experience with Teletek was with the Systemaster setups (multiple CPU boards). However, Teletek always crammed a lot of circuitry on their boards and tended to load the onboard regulators pretty heavily, so I'd start by checking to see if the regulated voltages on-board were up to snuff. Another thing that was very common for the time was for the RS-232C level translator chips to get zapped by static electricity, so I"d replace them also.

I'm assuming that your teminal is set up with the right speed, data bits, etc.
Click to expand...

9600 seems to be the comm rate, tried 7 and 8 bits. I've tried running a terminator on the bus too, BTW. Just desperate I guess...

I'll try to get those voltages tonight, and wow, who in the world will have those translator chips? I start searching right away.

Thanks for the input,
B.
 
Depending on the chip, places like Digikey or Mouser, or people on the forum.
What do you have in the way of test equipment, by the way, and what region are you located in ?
patscc
 
Well, this is embarrassing! No test equipment, I had one dual trace a few years back, but it died in transit in a prior move.

I imagine I will need to try to get myself back into possession of such things.

I live in Fernandina Beach, FL, we can see Cumberland Island GA from Brett's marina restaurant downtown Historic District, (but not Russia). Eons ago, I almost had the pleasure of going to Shemya Alaska, I was in the USASA, and that was one of very few places we had work. SPACOL. I might have been able to see Russia from there.

Bruce
 
On your board, below the two serial port connectors, you should see two SN7488's and two SN7489's. Edit: As Chuck(G) pointed out below, I got confused, meant 1488's and 1489's.
These are the level translators mentioned earlier. They're pretty standard. I'm gonna assume they're not socketed ?
Are you sure you've got serial lines hooked up properly with regards to handshake and all that ?
patscc
 
Last edited:
Um, I don't think that's right, Pat. A SN7488 is a PROM.

I believe you mean MC1488 and MC1489, EIA transmitter/receivers. They were very common--I don't think there should be any problem finding them).

I'm also assuming that you have the correct cable (straight-through for DTE-to-DCE; "null modem" otherwise). Before you go swapping chips, you should probably check the voltages on the DB25 going into your terminal. Pins 2 and 3 are probably the most important, with pin 7 for ground.
 
Here's the board:
http://i.imgur.com/8tiYn.jpg

The place you mention has 1488's and 1499's, socketed I.C.s on my board.

I will need time to do my homework on even the basics of how to implement those handshake settings, even the bit count, parity, etc.

On the plus side this gives me hope; as I said at the top, I'd be happy to discover the board worked and all that was required was me being up to the task.

Bruce
 
Chuck(G) said
Um, I don't think that's right, Pat. A SN7488 is a PROM.
I believe you mean MC1488 and MC1489, EIA transmitter/receivers
Click to expand...
You're right, of course. Got my families mixed up, sorry for any confusion. Like Chuck(G) said, they're pretty common, and there are also modern replacements available.
patscc
 
Thanks for the detaied shot of the board--that enabled me to immediately see something wrong. There's no RAM on this board--it can't possibly run.

You'll want to add some RAM to your system before you go much further.
 
What would go in there ? 6116's ? I have a doc for a similar board, which uses DRAM, so obviously not applicable here. I can't get the url past our firewall. Is there an alternate location for the image?
patscc
 
Off topic, but on target

Off topic, but on target

I am always amazed at the helpful folks out there, who know so much, and share!

If I could get you all to my favorite pub, here in Fernandina Beach, O'Kanes, I'd have a couple rounds of REAL Guiness in front of you. Or whatever your pleasure is, they even have great iced tea.

I am now going to try again to find that handshake assignment; 4 and 20 and all that. It doesn't show up in the menus for my VT 520 so far, but I'll look some more, then try to emulate older terminals till I find it.

That and the 7 v 8 bit word, stop and parity specs should be in my tech manual I got from Herb. I shall read tonight, big pile of papers though. :) You know I'll break out the trumpet when I get this act together.

Back to having fun again.

B.
 
Chuck(G) said:
Thanks for the detaied shot of the board--that enabled me to immediately see something wrong. There's no RAM on this board--it can't possibly run.

You'll want to add some RAM to your system before you go much further.
Click to expand...

Doh, I think I can follow you on that, :) , I thought those big sockets were for something else.

Some folks think I'm a computer wizard, I build a mean dual Xeon or a near 5GHz yet cool Sandybridge, but I feel downright puny in the company of this forum.

OK, back to my work.

All comments appreciated muchly,
B.
 
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