Tek/Sony 308 ROMs


I was wondering if anyone has a backup of the ROMs in the Tek 308? I have not found them on the Internet so far.

They are 2316s and 2364s, two each.



Peter H

Take a look at, three of the four images are there.

I just tried to read out the missing U430 from my 308 with my EPROM programmer but it came back all 0xFFs.
There are three chip selects that were apparently also mask programmable, i.e. one would have to make an adapter first to tie them to the correct logic level.
I'd guess that's the reason nobody has uploaded it yet.


Aren't the 2315 and 2364 mask programmed ROMs? Do they suffer from "ROM rot"?

Looking at the data sheets, 1) they show no timing diagram or voltage levels for programming the 2316 or 2364, and 2) they specifically say that the chips are "Designed to replace two [2708/2732] [8K/32K] EPROMS [to] eliminate the need to redesign printed circuit boards for volume mask programmed ROMS after prototyping with EPROMS."

Just saying that if Tony is experiencing some problem with his scope, maybe the mask-programmed ROMs are not the problem (that's probably not what he wants to hear. Sorry).



I am not having a problem with my 308, just that I like to have backup code for the devices I own. I have only had a couple of EPROMs fail in the last 20 years but when you need code there is no substitute. I agree with Jeff that it is unlikely ROMs go bad, but like any other component, they could. It is also a pain in the neck to read these as they don't generally show up as supported components on EPROM/Flash programmers.

Late last night I found a set of ROM codes from It was not where I expected so missed it the first time. It has at least one bad ROM download, the U430. It had a blank code checksum and looking at the code, it was blank. I checked the W140 site and it does have three of the ROMs. I am going to pull my other three ROMs and read them and compare to the other two sites images and see if I can confirm a good copy of all four to repost. I typically save a binary, hex and motorola version of code so will include these when I get done.

Most of the components in the 308 seem to be off the shelf or relatively easy to replace so once I have the ROM code I should not have much trouble if I ever have to repair it. I have many other more advanced logic analyzers and serial analyzers, but I got the 308 to play around with signature analysis. It is small and cheaper than most other signature analyzers, and can be used on slower/vintage projects from a similar era.


Peter H

Hi Tony,

I was able to read out U430 (base address 0x0000) from my 308 by tying pin 21 low.
A quick look at the disassembler listing appears fine (interrupt jump table, initialization etc.)
I've uploaded the missing binary to TekWiki. Please feel free to send an update to KO4BB too.




Looks like the two 2316Es have different CS levels. When one read ok and the other did not, with my fixture, I went to the datasheet and realized the CS pins are programmable. I looked at the schematic and see two of them on U486 are shown grounded but I could not find the third CS pin anywhere on the schematic. I would have to assume it is floating or pulled down internally. I assume the chip is always enabled.

I have zipped the ROMs in hex, bin and S format and uploaded them to KO4BB. Also in the zip is some info about the ROMs related to the 308 and the checksums. I don't have an account to tekwiki so thanks for uploading there.


Peter H

Yep, that's what I wrote earlier - "chip selects that were apparently also mask programmable".
The 2316 in U430 is code at address 0x0000 whereas the other 2316 chip is the character generator and as such is always enabled.