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Charles1
February 18th, 2015, 02:04 PM
Hello,

I joined this forum because I have just acquired
a EAI TR-20 analog computer. My desire is to sell
it.

I have a couple of questions. First, I am hesitant to
plug in the power cord, because of possibly damaging it
right off the bat. I don't think that could happen, but
I'm not sure, so my first question is should I power it up?

Secondly, is there a forum member interested in buying it.
It is missing what appears to have been the upper half of the
case, that would have gone over the patch cord tower. It is
also missing the patch cords.

Thanks, Charles

daver2
February 20th, 2015, 10:11 AM
Hi Charles1 and welcome to the forum.

If it was me - I would first visually inspect the power supply for any signs of damage and/or potential problems.

It will probably require a 'clean out' as these things have usually been stored in the back of a garage or somewhere else!

Obtain all of the documentation (most of it for the EAI equipment is online if you look).

Check all the fuses (and cross-check with the documentation to make sure the correct fuses have been fitted) and (most importantly) buy some spares!

Inspect things such as the capacitors especially - as these will almost certainly 'dried up' or could be leaking. They will probably not do their job properly and could go 'bang' if you powered it up. Usually items such as electrolytic capacitors here should be replaced as a matter of course.

Disconnect the power supply from the rest of the analogue computer and get a competent electrician to (a) check the earth connection [safety issue] and (b) check out that the electrical insulation etc. is OK.

If things look OK in the safety department (you don't want an electric shock or anything) then power up the unit and check that the power supplies are providing the correct voltages.

If you smell smoke or see flames - turn off instantly (!).

Yes, I would be interested in buying - however I am in the UK and I suspect (from the spelling of analog) that you are in the States. I suspect that the shipping costs will be prohibitively expensive however...

Dave

Charles1
February 20th, 2015, 11:53 AM
Dave, thank you for your considered reply.

However, and understandably, the moderators took a couple of days to post my first message, and in the meanwhile I got antsy and a few minutes ago posted it on Ebay. Then I returned to the forum to try to post a message in the Auction thread regarding the listing, when I saw my first post and your reply. Having already listed on Ebay and noting in the description that I haven't powered it up, at this point I've decided not to power it up.

Forgive me, I know you spent time on your reply, and I will cut and paste it for future use. I will note that the ebay listing is "http://www.ebay.com/itm/EAI-Pace-TR-20-Analog-Vintage-Computer-/181672277570?"

Thank you again, Charles

g4ugm
February 21st, 2015, 12:09 AM
Hi Charles,

I have an EAI-TR10 which is very similar to the TR-20. When I first got mine I used a variac to bring the power up slowly. The PSU is the only think you are likely to damage, but as it uses mechanical chopper relays to stabilize the OP-Amps its unlikely to work. After cleaning out some rust from inside the chopper relays mine mostly works. You can see it drawing some plots on a pen chart recorder here:-

https://www.youtube.com/watch?v=aLBSBqaVcxc

The TR-20 service manual is available on a number of web sites.

Dave

P.S. don't be surprised if it doesn't sell. By setting the starting price as high as you have you have you have removed the chance of some one to get a bargain. These Comdyna GP-6, which are probably more desirable because of the smaller size:-

http://www.ebay.com/itm/Rare-Vintage-Comdyna-GP-6-Analog-Computer-Linear-Synthesizer-Synth-/141545723770

have been doing the rounds for ages and keep getting re-listed. On the other hand this rather splendid example sold

http://www.ebay.com/itm/Comdyna-LGP-20-GP-10-x2-MicroHybrid-linked-analog-computers-/191430110084

for $765 after starting at $1. Remember when you search "completed listings" returns items that didn't sell. To see what things fetched use "sold listings".

Charles1
February 21st, 2015, 05:41 AM
Starting price is lowered to $0.01, as I agree with your sentiments, and have done that
in the past. E-bay is prompting suggested starting prices now, and I succumbed. Nothing
to do with the TR-20 itself.


" Dave

P.S. don't be surprised if it doesn't sell. By setting the starting price as high as you have you have you have removed the chance of some one to get a bargain. These Comdyna GP-6, which are probably more desirable because of the smaller size:-

http://www.ebay.com/itm/Rare-Vintage-Comdyna-GP-6-Analog-Computer-Linear-Synthesizer-Synth-/141545723770

have been doing the rounds for ages and keep getting re-listed. On the other hand this rather splendid example sold

http://www.ebay.com/itm/Comdyna-LGP-20-GP-10-x2-MicroHybrid-linked-analog-computers-/191430110084

for $765 after starting at $1. Remember when you search "completed listings" returns items that didn't sell. To see what things fetched use "sold listings".[/QUOTE]

g4ugm
February 21st, 2015, 06:52 AM
Best of luck with that. I think others will be interested to know E-Bay is suggesting starting prices, I hadn't realised! I find its attempts to sell me things when I don't win Analog Computers pathetic. Any idea how much it would cost to ship to the UK (really)...

dave_m
February 21st, 2015, 12:36 PM
starting price is lowered to $0.01, as i agree with your sentiments

Charles,
Another possible issue with the posting is that you stated shipping at $12.20. People may think you will ship in a cardboard box. You should have either posted a fair price for proper packaging and handling or free shipping as an incentive, stating that you will carefully package and ship such an important piece of computer hardware.

g4ugm
February 26th, 2015, 09:40 AM
Nice to see its had some sensible bidding. I would really like one of these but its going to go for a big price and shipping to the UK would be silly.,..