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EAE Issue/Question

BitWiz

Experienced Member
Joined
Sep 7, 2021
Messages
211
Location
Glen Ellyn, Iil
I just received M8340 and M8341 boards from an ebay purchase. When I put them in my PDP-8/E the system did not seem to work properly at all.

I removed the EAE boards and reconnected the main three CPU boards and everything is working again.
After removal I examined the EAE boards and found that it looks like both boards missing the tantalum caps near the bottom of the boards. On the M8341D that would be C33, C34 & C35 (6.8uF @ 35V) and on the M8340E board that would be C35, C36 & C37 (6.8uF @35V).

I cleaned up the contacts and removed what may have been some kind of trace scratch that led to a short and now it is running my rudimentary test.

Should I replace the CAPs? Can I use electrolytics instead of tantalums?

I will run the full maindecs when I get a chance.

Thanks for the help,

Mike

I don't know how to setup the signature line so here is my signature line:

I am a PDP-8 fanatic living in the Chicago area and I am looking for any surplus PDP-8 related hardware and documentation. I am specifically in need of a TC08 or TD8E dectape controller, M933 cables for the RK05, additional TU56s and RK05s, PC08, M8650, programmable timer, DECTapes, RK05 Packs (16 sector PDP-8 style), +10V & -15V or +5V and -15V power supply for the TU56, DECTape spools, TU56 Mounting shelf and spacer block (7408321 & 7408322). Please feel free to contact me if you have any of the above or just to talk:).
 

BitWiz

Experienced Member
Joined
Sep 7, 2021
Messages
211
Location
Glen Ellyn, Iil
Roland,

Here are the board versions:

M8330
M8340E
M8341D
M8310B
M8300A

Thanks,

Mike

I don't know how to setup the signature line so here is my signature line:

I am a PDP-8 fanatic living in the Chicago area and I am looking for any surplus PDP-8 related hardware and documentation. I am specifically in need of a TC08 or TD8E dectape controller, M933 cables for the RK05, additional TU56s and RK05s, PC08, M8650, programmable timer, DECTapes, RK05 Packs (16 sector PDP-8 style), +10V & -15V or +5V and -15V power supply for the TU56, DECTape spools, TU56 Mounting shelf and spacer block (7408321 & 7408322). Please feel free to contact me if you have any of the above or just to talk:).
 

Roland Huisman

Veteran Member
Joined
Mar 24, 2011
Messages
1,324
Location
The Netherlands
Should I replace the removed capacitors?

Yes I would do that. But I don't think it would make a difference in the fact that the
boards not working at the moment. You have the newer model EAE boards and an
old CPU board set. Like Tom says, check the story from Mike Thompson
 

BitWiz

Experienced Member
Joined
Sep 7, 2021
Messages
211
Location
Glen Ellyn, Iil
The main CPU runs my mini test program though I haven't run the maindecs on it yet. I'm not sure about the EAE.
 
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