Heathkit ETA-3400 with unusual switch

[Floppies_only]

Gang,

My Heathkit memory i/o accessory came from ebay with a ten position switch located about one inch from the left edge of the front panel. The switch is the type which has two buttons and a window that displays the numbers 0 through 9. If you push the button on top the number is decreased by one and if you push the button on the bottom it is increased by one. All the other ETA-3400s I've seen in pictures lacked this switch. When I got mine I just assumed that it was for the purpose of changing the baud rate of communications with the terminal. My question is if anybody knows of another example with a switch like this and what it's for?

I also wonder if ETA-3400s come with less than the full amount of memory (4K) and if not can they be filled with 2112-2 SRAM chips or do they take another type?

I've got another question, too. I've been told that the connector on the ET-3400 is a 40 pin ISA connector that is commonly found on ISA hard disk controllers. Does anyone have a dead card that the connector can be salvaged from that is surplus to needs?

Sean

 

[Chromedome45]

Use a 40 pin IDE connector and a 40 pin header if one is not one you 3400. Works great. Also that switch I do not have in my ETA-3400 never heard of it. You may also have to make some mods to the ET-3400 especially if you have the original 3400 to make it work with the ETA. Need to bring the 8 data lines to the I/O connector plus a couple more control lines. Look here and grab any manuals you might be missing such a the MODification kit instructions if it is not done already. Hope this helps.

 

[Floppies_only]

Use a 40 pin IDE connector and a 40 pin header if one is not one you 3400. Works great. Also that switch I do not have in my ETA-3400 never heard of it. You may also have to make some mods to the ET-3400 especially if you have the original 3400 to make it work with the ETA. Need to bring the 8 data lines to the I/O connector plus a couple more control lines. Look here and grab any manuals you might be missing such a the MODification kit instructions if it is not done already. Hope this helps.

I looked online for a 40 pin connector, but I couldn't find one. I looked in my Mouser catalog, too, to no avail.

I also found the modification instuctions here:


http://www.classiccmp.org/dunfield/heath/index.htm

Sean

 

[Chromedome45]

Yeah that's the link I forgot to insert! Boy am I a dork. Anyway the connector you need you can find here: http://www.jameco.com/webapp/wcs/st...10001&pa=53532&productId=53532&cid=PDF CAT 74

The ETA-3400 takes 2114 Static RAMS also available at Jameco here: http://www.jameco.com/webapp/wcs/st...gId=10001&freeText=2114&search_type=jamecoall

I think it takes 8 total RAM chips and any speed will do. At least this time I remembered to paste in the links

Hope this helps you out.

Oh here is something to try with your ET-3400. It adds an EEPROM as a way to store programs! http://timothyweber.org/heathkit

and here: http://timothyweber.org/et3400eeprom

Have Fun!

 

[Floppies_only]

Yeah that's the link I forgot to insert! Boy am I a dork. Anyway the connector you need you can find here: http://www.jameco.com/webapp/wcs/st...10001&pa=53532&productId=53532&cid=PDF CAT 74

The ETA-3400 takes 2114 Static RAMS also available at Jameco here: http://www.jameco.com/webapp/wcs/st...gId=10001&freeText=2114&search_type=jamecoall

I think it takes 8 total RAM chips and any speed will do. At least this time I remembered to paste in the links

Hope this helps you out.

Oh here is something to try with your ET-3400. It adds an EEPROM as a way to store programs! http://timothyweber.org/heathkit

and here: http://timothyweber.org/et3400eeprom

Have Fun!

Thanks for the info! I'll be ordering real soon.

Sean

 

[Floppies_only]

Gang,

My Heathkit memory i/o accessory came from ebay with a ten position switch located about one inch from the left edge of the front panel. The switch is the type which has two buttons and a window that displays the numbers 0 through 9. If you push the button on top the number is decreased by one and if you push the button on the bottom it is increased by one. All the other ETA-3400s I've seen in pictures lacked this switch.

I figured out what the switch probably is by reading the assembly manual (after I dug it out). There are three places for jumpers inside the I/O accessory to set the baud rate used on the connection between the accessory and the terminal. I don't feel like taking my accessory apart to confirm this, but I am sure that the switch is wired to connect different jumpers to set different baud rates. It seems like a useful modification.

Sean

 

[billdeg]

old thread I know...but coincidentally I currently happen to be going through the process of installing the recommended et-3400 main CPU unit mods to make it run with the ETA-3400, and mine has the same baud rate toggle switch on the front. Electrically it checks out to match the manual jumpers. Very simple.

 

[billdeg]

http://vintagecomputer.net/browse_thread.cfm?id=553
Project Notes and photos stepping through modifying an ET-3400 to use the ETA-3400

Pic of the system. The unit on the bottom is the ETA-3400 and facing this picture the baud rate toggle is on the front left, the two red buttons (up/down).

Works!

 

[wheagy]

ET-3400-A modkit manual

ET-3400-A modkit manual

Ok, reviving this thread once again. I have an ETA-3400 kit (I/O) that is 99.9% complete (all the parts). I built most of it and am currently at the mod for the ET-3400. I have an ET-3400-A, but the ETA-3400 modkit manual that it came with it is only for the ET-3400. I found some manuals online, but they all seem to be like this one...
http://vintagecomputer.ca/files/Hea...ith ET-3400 Microprocessor Trainer Manual.pdf
and are missing the Pictorial 2-4 (fold-in page 2) as referenced on page 17.



The circuit boards of the ET-3400 and the ET-3400-A seem to be slightly different and I'm guessing this fold-in has the detail on how the 8 wire ribbon cable is connected.

Does anyone have a PDF that includes the fold-in (or even a cell phone pic of the fold-in would be helpful).

Thanks!

Win

 

[wheagy]

It looks like Pictorial 2-4 is actually part of the ET-3400 assembly manual, so I was able to find the picture I needed. I assumed it was part of the ETA-3400 material so was looking for it there.

Thanks,,
Win