Donner 3500 - Early Portable Analog Computer

[billdeg]

Here is my page for the Donner 3500 computer. I have not yet cleaned it yet, or tested the tubes. It's similar to the Heathkit EC-1, except that the amplifiers are stored on cards one can remove to clean and repair. Kind of cool.

http://vintagecomputer.net/browse_thread.cfm?id=247

Bill

 

[billdeg]

Question

If you look at this picture, and the tube silkscreens (for example)
http://vintagecomputer.net/donner/donner_3500_amplifier-front-1.JPG

Is there a way by looking at the tubes or other components from the late 50's early 60's to id the date the components were made, similar to the later TTL chips have a date stamp?

bd

 

[Chuck(G)]

Question

If you look at this picture, and the tube silkscreens (for example)
http://vintagecomputer.net/donner/donner_3500_amplifier-front-1.JPG

Is there a way by looking at the tubes or other components from the late 50's early 60's to id the date the components were made, similar to the later TTL chips have a date stamp?

bd

Very cool, Bill! Is the "Donner" the same as in "Systron Donner"?

Many of the tubes have lot numbers on them, but it's pretty likely that any information as to production dates is likely lost. Have you checked the chassis for stamps or maintenance labels? I've got an old BuShips receiver that I was delighted to find the maintenance log penciled in under an access cover. (It was last serviced in Okinawa in 1945).

 

[billdeg]

Very cool, Bill! Is the "Donner" the same as in "Systron Donner"?

Many of the tubes have lot numbers on them, but it's pretty likely that any information as to production dates is likely lost. Have you checked the chassis for stamps or maintenance labels? I've got an old BuShips receiver that I was delighted to find the maintenance log penciled in under an access cover. (It was last serviced in Okinawa in 1945).

Yes Donner became Systron Donner in early 1960. I have not checked for service stamps, etc. I still need to take apart, clean the computer, test continuity, etc. as well.

Bill

 

[tezza]

Cool machine Bill,

What would these early transportables be used for. Anyone know?

Tez

 

[billdeg]

According to the soon-to-be-uploaded Instruction Manual, all kinds of field and classroom uses. There is a section of the manual with a list of applications. When I post this I will let you all know.
bd

 

[tezza]

It certainly must be something to have these REALLY OLD vintage computers. valves. Wow. I'm assuming parts would be near impossible to come by.

Anyway good luck with getting it going Bill.

Tez

 

[Dwight Elvey]

According to the soon-to-be-uploaded Instruction Manual, all kinds of field and classroom uses. There is a section of the manual with a list of applications. When I post this I will let you all know.
bd

Hi Bill
The biggest issue with these old machines is the electrolytics. They
should be reformed. You'll need to make up a number of patches.
to check the opamps. It isn't too hard, you just wire them as 1:1
inverters and use the meter and a set point pot to ensure that they
track.
After looking at your pictures I'm sure the patch board I have is
not the same model.
Dwight

 

[Dwight Elvey]

Question

If you look at this picture, and the tube silkscreens (for example)
http://vintagecomputer.net/donner/donner_3500_amplifier-front-1.JPG

Is there a way by looking at the tubes or other components from the late 50's early 60's to id the date the components were made, similar to the later TTL chips have a date stamp?

bd

Hi Bill
I noticed it has some of those metal encased capacitors.
These often have date codes.
The tubes often have date codes as well.
Dwight

 

[billdeg]

I should have something to report in a week and a half.
bd

 

[billdeg]

Tubes - all tested OK. That's encouraging, but the electronic connections, capacitors, etc are more likely to have faults due to age.

 

[altec1]

I have one too S/N # 124

 

[billdeg]

There is one for sale on Ebay now too

 

[Dwight Elvey]

Hi
If interested, I can show the patching I do to make
a spiraljyra like plot.
I just combine two oscillators, one fast and one slow.
Changing parameters, one can do a number of intersting
things, like ovals on top of spheres.
It uses two integrators for each oscillator. There is a trick
I do the keep it from dampening out because of
lost phase shift.
Dwight

 

[altec1]

I didn't see it on Ebay. I was thinking of selling mine. It would need a good cleaning. Any ideas of what it would be worth in it's present state and if I restored it. thanks Keith in Victoria

 

[Dwight Elvey]

Hi
Try the number 190436568866. Right now, it has one bid at
$500. I expect it to go higher but you never know which way the wind
blows.
I'd wait at least 3 months before putting another one up unless
you think the third highest bid is fine.
Dwight

 

[Dwight Elvey]

Hi
If interested, I can show the patching I do to make
a spiraljyra like plot.
I just combine two oscillators, one fast and one slow.
Changing parameters, one can do a number of intersting
things, like ovals on top of spheres.
It uses two integrators for each oscillator. There is a trick
I do the keep it from dampening out because of
lost phase shift.
Dwight

Hi
Actually it takes 3 amps, two of them being inergrators
for each oscillator. Actually, the slow speed one doesn't
have a problem since it make only one revolution. It is
the high speed one that looses a little bit on each
cycle.
Dwight

 

[billdeg]

I am interested.

 

[altec1]

Looks like I found some more parts to this beast! I think I will probably sell the unit as this doesn't really fit into my mancave. I restore test equipment from the 50's and 60's

 

[Ole Juul]

. . . thanks Keith in Victoria

Did you say Victoria? Have a look at this thread. We have a job for you. hehe