Well it's not that ROMs themselves, it's the GLUE which controls whether the ROMs are enabled or not. The pinout of GLUE ROMN which goes directly to the ROMs isn't being set low... which is required to allow the ROMs to output data.
So it's either my GLUE is borked or my socket isn't soldered...
Thanks for your write up. I'm facing a similar issue - though my board isn't even starting.
I socketed every IC that was socketable - all the PLCCs and DIPs.
When I read about the flux I looked at mine and I thought it was a bit schmeary so I removed all PLCC ICs and washed the crap out of it...
I did some scoping and found that ROMN (ROM enable, pin 27) of the GLUE stays high. This goes to the 29F010’s output enable (pin 24) active low. The ROMs never output anything! Which is true; the address lines initially get some activity but not the data bus.
i also sounded out all the address...
Okay got some new VRAM, EPROM. Still getting not much other than horizontal stripes.
To program the EPROM I doubled each ROM from the GitHub repo:
cat u1 u1> u1_128k
cat u2 u2> u2_128k
etc
and burned and installed into sockets
And as a bonus I have been working on removing components from a second original SE/30 board - the utility of the sockets now coming into play by being able to test another set of ICs (that is assuming the sockets are helping and not hindering).
I think if I had a known good set of ICs I would...
Thanks for your replies! Very much appreciated!
Yes I directly burned the ROM images from the Github repo without any modification.
Then read them back to verify checking the check sum hashes which matched.
Each chip was carefully removed and then painstakingly cleaned.
First I removed residue...
Yes they are bridged. I don't think the screen would have shown anything without access to the ROMs?
Or does the screen refresh completely independently from the CPU using the PLA logic and video rom only?
Also there are a few other new components like the 30-pin SIMM sockets and the fuses.
So here's my progress on my reloaded board.
I opted to reuse as much as possible from a board that was untested as it had capacitor and battery damage.
I was going to reuse the ROMs from the damage SIMM (was mainly around the contacts area) and foolishly assumed that the ROMS from the SIMM were...
I've almost completed my SE/30 reloaded board - I chose to go with the PLCC ROM sockets.
What ROMs do I need for these? Will this be ok?
AT27C512R-15JC (64KB 150ns speed)
Okay so the new DA7052 op-amps arrived. I took the old one out, put in a new one and BINGO, we got sound from the internal speaker.
It couldn't be anything else.
The old one still looked completely fine.
So that's everything AFAIK working. Now I can finish "building" the system and install an...
yes, I do - a nice, strong, clear chime so presumably either trace going to the speaker - which I doubt as the board looks really clean and good or more likely the opamp.
i don’t have a spare for this so I will order one in.
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