Burroughs BIP-8820 reverse engineering help (signetics chip numbers).

[clu]

Hello,

I've acquired several Burroughs BIP-8820 Nixie Decade Counter/drivers. There is no pinout or detailed datasheet on how to them as far as google is concerned. A general description is given here (http://tube-tester.com/sites/nixie/dat_arch/BSG-Bulletin_1061K.pdf) on page 11. I have been able to poke around and find that pin 4 is common, pin 2 is +5V and pin 6 is the anode (with resistor). It's quite similar to the BIP-8804 decoder/driver with datasheet here (http://www.decadecounter.com/vta/pdf2/BIP-8804.pdf).

Eventually I found a broken one and picked it apart to figure out what the other pins do. From the 1061 sheet I know there need to be 4 BCD outputs and a reset (possibly more stuff). After removing all the epoxy I found two old Signetics chips in there. The Signetics logo is the one used in the late 60s but I can't find any data using the part numbers on the chips. Can anyone identify these chips (image links below)(I'm assuming one decade counter with BCD output and a nixie driver)? I'd like to make an unofficial BIP-8820 datasheet for anyone else out there with these...

http://i.imgur.com/V2Cos.jpg

http://i.imgur.com/3nn1i.jpg

[Charles MacDonald]

On 12-03-11 08:12 PM, clu wrote:

> The Signetics logo is the one
> used in the late 60s but I can't find any data using the part numbers on
> the chips. Can anyone identify these chips (image links below)(I'm
> assuming one decade counter with BCD output and a nixie driver)

> http://i.imgur.com/V2Cos.jpg
>
> http://i.imgur.com/3nn1i.jpg

Could they have a Burroughs "House number"? Not uncommon in solid state
stuff.

--
Charles MacDonald Stittsville Ontario
cm...@zeusprune.ca Just Beyond the Fringe
http://users.trytel.com/~cmacd/tubes.html
No Microsoft Products were used in sending this e-mail.

[David Forbes]

On 3/11/12 5:12 PM, clu wrote:
> I found two old Signetics chips in there. The Signetics logo is the one
> used in the late 60s but I can't find any data using the part numbers on
> the chips. Can anyone identify these chips (image links below)(I'm
> assuming one decade counter with BCD output and a nixie driver)? I'd
> like to make an unofficial BIP-8820 datasheet for anyone else out there
> with these...
>
> http://i.imgur.com/V2Cos.jpg
>
> http://i.imgur.com/3nn1i.jpg
>

Those are definitely Burroughs house numbers, since the number on the PC
board under the chip in the second photo has a number with the same format.

Good luck on the reverse engineering!

--
David Forbes, Tucson AZ

[clu]

Alright, here we go,

Important note: pin 4 is not common and pin 2 is not +5V (I wish I could edit my first post to avoid misinformation).

The numbers were definitely Burroughs house numbers. Fortunately there is this document (http://bitsavers.org/pdf/burroughs/icData/burroughs_IC_crossref.pdf) that at least lists the functions of the chips (page 61). I'm part of the way through a schematic of the BIP-8820-1 which certainly agrees with the functions of the chips. The 906 1627 1363 is a "BCD to Decimal Decoder/Driver." The 849 1627 1371 is a "Counter/Storage Register." Fortunately Signetics datasheets still exist here (http://bitsavers.org/pdf/signetics/_dataBooks/1972_Signetics_Full_Line.pdf). It appears that the 906 (BCD to decimal decoder/driver) is equivalent to a Signetics 7441 (page 2-40) and the 849 (counter) is equivalent to a Signetics 8280 (page 3-90). So I think I've found all the features of the BIP-8820-1 along with the pinout. 

I'll post the schematic and pinout soon after I do a good test.

Thanks for the tips!

~clu

[Fetguy]

I have a 1969 Signetics catalog and there was an older BCD-to-Nixie
driver called 8T01, also in 16 pin DIP, but with a different pinout
from the 7441. So if you find the pins are not working out, Google
the 8T01. I see a data sheet out there for it. They offered a few
different counters, but the 8280 was their basic BCD one, so that is
probably correct.

Best of luck with it!

On Mar 12, 6:57 pm, clu <nico.n...@gmail.com> wrote:
> Alright, here we go,
>
> Important note: pin 4 is not common and pin 2 is not +5V (I wish I could
> edit my first post to avoid misinformation).
>
> The numbers were definitely Burroughs house numbers. Fortunately there is
> this document
> (http://bitsavers.org/pdf/burroughs/icData/burroughs_IC_crossref.pdf) that
> at least lists the functions of the chips (page 61). I'm part of the way
> through a schematic of the BIP-8820-1 which certainly agrees with the
> functions of the chips. The 906 1627 1363 is a "BCD to Decimal
> Decoder/Driver." The 849 1627 1371 is a "Counter/Storage Register."
> Fortunately Signetics datasheets still exist here

> (http://bitsavers.org/pdf/signetics/_dataBooks/1972_Signetics_Full_Lin...).

[clu]

This driver definitely matches the 7441 pinout. Thanks for the heads up though.

I've tested the driver with the new pinout I worked out and everything works nicely. I'm attaching a schematic in case anybody else with the same problem stumbles across this in the future...

~clu

[threeneurons]

The counter output and reset is accessible, so if someone had 5 or 6 of these, they could make a clock out of them. Neat !

Thank you for taking the time to extract that information, and for sharing it with us !