Diablo 1620 problem

[John Garza]

Anybody seen a troubleshooting guide for the old Diablo printers?
I have the maintenance manual but there's no troubleshooting guide.

Mine powers up but doesn't print either via rs-232 or in local mode.
It was working fine last time I used it 4 years ago.
Has been sitting on a table under a bedsheet since then.
(I guess it decided to die in it's sleep!)

Please reply to this newsgroup, thanks!
-J

 

[mroberds]

Anybody seen a troubleshooting guide for the old Diablo printers?
I have the maintenance manual but there's no troubleshooting guide.

Bitsavers has a "product description" (which has setup/install
instructions) and a parts list, if those help:

http://bitsavers.trailing-edge.com/pdf/diablo/82332G_1610_1620_Product_Description_Dec78.pdf
http://bitsavers.trailing-edge.com/pdf/diablo/82334-02_1610_1620_Parts_Catalog_Aug78.pdf

Mine powers up but doesn't print either via rs-232 or in local mode.

One of the standard suspects for anything is the power supply. In a
quick turn through the maintenance manual, this thing monitors its +5,
+15, and -15 supplies, and refuses to work if any of them are out of
range. (Paper page 2-28, PDF page 42.) The spec (paper page 3-30, PDF
page 98) says the limits are 4.9 to 5.1 V, 14.5 to 16.0 V, and -14.5 to
-16.0 V.

In the product description, it also mentions a switch that shuts things
down when it thinks it is out of paper... maybe that switch is tripped?

Matt Roberds

 

[Hactar]

Bitsavers has a "product description" (which has setup/install
instructions) and a parts list, if those help:

http://bitsavers.trailing-edge.com/pdf/diablo/82332G_1610_1620_Product_Description_Dec78.pdf
http://bitsavers.trailing-edge.com/pdf/diablo/82334-02_1610_1620_Parts_Catalog_Aug78.pdf


One of the standard suspects for anything is the power supply. In a
quick turn through the maintenance manual, this thing monitors its +5,
+15, and -15 supplies, and refuses to work if any of them are out of
range. (Paper page 2-28, PDF page 42.) The spec (paper page 3-30, PDF
page 98) says the limits are 4.9 to 5.1 V, 14.5 to 16.0 V, and -14.5 to
-16.0 V.

You can probably rig a standard ATX power supply to provide those.
You'll have to provide your own momentary SPST switch, if the printer's
switch isn't.

 

[mroberds]

You can probably rig a standard ATX power supply to provide those.

You might be able to twiddle the +12/-12 V outputs of an ATX power
supply up/down to +15/-15 V, but I don't think any ATX power supply
could provide enough current on the -12/-15 V line. The power supply
spec in the Diablo maintenance manual (paper page 2-45, PDF page 59) is

+5V @ 4A (8A surge)
+15V @ 4A (10A surge)
-15V @ 4A (10A surge)

The manual does give full schematics for the power supply, so there is a
chance of fixing the original, if it turns out to be the problem.

Matt Roberds

 

[Hactar]

You might be able to twiddle the +12/-12 V outputs of an ATX power
supply up/down to +15/-15 V, but I don't think any ATX power supply
could provide enough current on the -12/-15 V line. The power supply
spec in the Diablo maintenance manual (paper page 2-45, PDF page 59) is

+5V @ 4A (8A surge)
+15V @ 4A (10A surge)
-15V @ 4A (10A surge)

Myeah, maybe not.

The manual does give full schematics for the power supply, so there is a
chance of fixing the original, if it turns out to be the problem.

My first guess would be a dried-out cap, if it's not something simple
like a cold solder joint or dead fuse.

 

[John Garza]

Anybody seen a troubleshooting guide for the old Diablo printers?
I have the maintenance manual but there's no troubleshooting guide.

Mine powers up but doesn't print either via rs-232 or in local mode.
It was working fine last time I used it 4 years ago.
Has been sitting on a table under a bedsheet since then.
(I guess it decided to die in it's sleep!)

Please reply to this newsgroup, thanks!
-J

Thanks all for the replies!
I haven't got around to tinkering with it yet. My Sol-20 is on the
bench for a flakey Micropolis drive. The Diablo is up next.

But it is pretty amazing it "died on the shelf"; the thing is built like
a tank. All the responses seem logical though - time dries out
electrolytic caps, and some slight corrosion or dust in a switch could
prevent conduction, etc.

Maybe I need to hermetically seal all my machines.
Maybe a big airtight antistatic bag filled with nitrogen?

I'm starting to feel like the repairmen in those old stories you hear
about the huge ancient computers. As soon as someone replaced a vacuum
tube, another would burn out some place else!

_john

 

[glen herrmannsfeldt]

(snip)

Thanks all for the replies!
I haven't got around to tinkering with it yet. My Sol-20 is on the
bench for a flakey Micropolis drive. The Diablo is up next.

But it is pretty amazing it "died on the shelf"; the thing is built like
a tank. All the responses seem logical though - time dries out
electrolytic caps, and some slight corrosion or dust in a switch could
prevent conduction, etc.

I have an HP 9810A calculator that I bought in pretty bad shape.
It looked like it had been out in the rain. I cleaned it up
(took out all the boards, washed them carefully and let them dry),
I might have tried a little to reform the capacitors, but only
a little. (They don't make capacitors like they used to.)

Turns out that only one part completely failed, and that is
the on/off switch.

I have a 20 year old car, where the on/off switch on the radio
failed. I took it out, soldered a wire across it, so now it
works fine. The on/off is on the volume control, so it still
seems to be off when you turn it off.

Maybe I need to hermetically seal all my machines.
Maybe a big airtight antistatic bag filled with nitrogen?

-- glen

 

[mroberds]

All the responses seem logical though - time dries out electrolytic
caps, and some slight corrosion or dust in a switch could prevent
conduction, etc.

Sometimes it's really simple. This spring, my circa-1993 Laserjet 4
refused to power on, right as I wanted to print out my tax return. A
little digging revealed that a wad of dust had gotten into the line
power switch. Removing the dust made it go and it's been working ever
since.

Maybe I need to hermetically seal all my machines.

Or, get a zillionaire interested in them, and he will pay a staff to
maintain them. http://www.livingcomputermuseum.org/

Maybe a big airtight antistatic bag filled with nitrogen?

Protip: You used to be able to get free nitrogen from the phone company,
but they are letting the copper infrastructure rot on purpose, so they
don't care about leaks anymore. Go to a shopping mall or similar large
parking lot and get free nitrogen from car tires that have green valve
caps on them. (If you're feeling really polite, replace it with a 78%
nitrogen/21% oxygen/1% otherstuff mix.)

I'm starting to feel like the repairmen in those old stories you hear
about the huge ancient computers. As soon as someone replaced a
vacuum tube, another would burn out some place else!

The story I heard was that they ran the tube filaments at nominal
voltage, or maybe a little under nominal. On Tube Day, they ran the
filament voltage up to 10% or so above nominal, and maybe flicked it on
and off a few times, and replaced all the ones that burned out.

Matt Roberds