sander wrote on 2024-09-28, 07:04:

Thank you! So there is no bracket to attach the cache module to? It looks like the module will fit, but I would like to be sure if the protruding edge will fit. Can you measure how much room you have from the top of the cache socket?

No, no bracket like the desktops. It’s just under 5.5cm from the top of the connector to the bottom of the PSU (so just over 2 inches).

nizmow wrote on 2024-09-28, 03:35:

Here are some photos of the Prolinea MT 4/50. Just taking it apart for cleaning! Very spacious design, and the same cache port up top.

That is what the mt looks like... one of the 2 boards I have that work is an mt. The other shows up as the 800 series in the bios. The only differences are revision numbers/letters. And colors of the memory slots and board dye(my original 860cds is darker green with white memory slots). The 833 and mt board have a brownish color like yours with black memory slots.
So far all I've seen with the light brown Vesa style slot. I so hope they are all the same.

It works! Still need to conduct some stability tests though, see results below. As the components are new, soldering was really easy. But if I'll do a batch of PCBs I will definitely use a stencil..

This is showing L2 cache:

And so is this:

Here I run debug to read the cache config register from the VL82C483, you see it returning "B4" which is 10110100. Looking at the manual it means it sees two banks, One Wait state (I'm definitely going to bios patch this), 9-bit, dirty bit enabled and 256KB!

👍 😁
The third picture starting at 30 has no 27 regions, thats 31'st MB and up not L2 cached?
Wonder why jlc put its stupid tracking number in random spot and not in the JLCJLCJLCJLC.

Fantastic! Is now the time when we should consider ordering our own boards, or is there more tweaking to go? Sounds like I should order some EEPROMs for this thing, too. I think the BIOS (at least on my MT) is write-once.

Yeah!, congratulations!

I'll just wait till things are confirmed working correctly.

Cheers,

rasz_pl wrote on 2024-10-01, 21:04:

👍 😁
The third picture starting at 30 has no 27 regions, thats 31'st MB and up not L2 cached?
Wonder why jlc put its stupid tracking number in random spot and not in the JLCJLCJLCJLC.

Under the watchful eye 😉 Forgot to solder one pin, all should be fine now.. Next some testing with 1MB of ram and zero wait states.

I could do a small production run for 10 PCBs, I'll make a BOM for 10 pieces and I'll come back with a price.

Great...
Got the Prolinea MT board, waiting in a box, for a build... Now it can be complete with full L2 cache.

https://theretroweb.com/motherboards/s/compaq … rolinea-mt#docs

Followinf this tread.

sander wrote on 2024-10-02, 10:15:

Under the watchful eye ;-) Forgot to solder one pin, all should be fine now.. Next some testing with 1MB of ram and zero wait st […]
Show full quote

rasz_pl wrote on 2024-10-01, 21:04:

👍 😁
The third picture starting at 30 has no 27 regions, thats 31'st MB and up not L2 cached?
Wonder why jlc put its stupid tracking number in random spot and not in the JLCJLCJLCJLC.

Under the watchful eye 😉 Forgot to solder one pin, all should be fine now.. Next some testing with 1MB of ram and zero wait states.

I could do a small production run for 10 PCBs, I'll make a BOM for 10 pieces and I'll come back with a price.

The attachment IMG_20241002_121317.jpg is no longer available

Come on, I'm interested. Once you have done and ready to sell boards, I want to in your line up to purchase. All I have is paypal.

I'm also good on assembling these cache board due to my hobby and my work also involves soldering.

Cheers

sander wrote on 2024-10-02, 10:15:

I could do a small production run for 10 PCBs, I'll make a BOM for 10 pieces and I'll come back with a price.

I’m keen! Just in the process of de-rusting and doing some plastic welding on the Prolinea MT so this would be going right into that bad boy.

Excellent work Sander, I'd like to order two boards.

A post with a summary of the chips used in the final iteration would be appreciated (256K would be nice for my scenario).
I'm a complete novice/newbie at ordering but can do soldering.
It's like Christmas and New Year's rolled into a single package, exciting times ahead.

I am violently shaking my debit card and cash at the phone screen... has it gotten to you somehow? Lol
I dont know how to say thank you enough... and I will gladly be in line for 1 please...
You are just a master of cache.... and compaq!
I await the ability to buy, fully clenched and ready!

This is awesome project! I have Prolinea 4/50 with 164560-001 motherboard, which is very similar (identical?) to 4/66 MBs and have that darn unobtainium coast slot. Some of 4/50 MBs don’t coast slot at all.

I’m definitly interested in purchasing a ”test subject”!

CharlieFoxtrot wrote on 2024-10-03, 17:37:

This is awesome project! I have Prolinea 4/50 with 164560-001 motherboard, which is very similar (identical?) to 4/66 MBs and have that darn unobtainium coast slot. Some of 4/50 MBs don’t coast slot at all.

I’m definitly interested in purchasing a ”test subject”!

Keep in mind that 128K/256K open source cache module is only for VLSI 483 chipset boards known to work. There is another type of cache module 64K with Intel 485 cache controller is only for few earlier compaq computers with busy compaq designed chipsets that totally covered whole area of motherboard, by the way, 64K module is extremely rare.

Cheers,

pentiumspeed wrote on 2024-10-03, 17:43:

CharlieFoxtrot wrote on 2024-10-03, 17:37:

This is awesome project! I have Prolinea 4/50 with 164560-001 motherboard, which is very similar (identical?) to 4/66 MBs and have that darn unobtainium coast slot. Some of 4/50 MBs don’t coast slot at all.

I’m definitly interested in purchasing a ”test subject”!

Keep in mind that 128K/256K open source cache module is only for VLSI 483 chipset boards known to work. There is another type of cache module 64K with Intel 485 cache controller is only for few earlier compaq computers with busy compaq designed chipsets that totally covered whole area of motherboard, by the way, 64K module is extremely rare.

Cheers,

Yeah, I should have the correct type of MB. At least I think so.

These Compaq motherboard revisions can be pretty confusing. I’ve seen 4/50s in YT with identical looking cases, but they have a MB with quite different layout, no cache slot and they have Varta battery instead of a coin cell. Retroweb also has this MB listed for 4/50. My MB is this one and listed in retroweb as 4/66 and also 4/33:

https://theretroweb.com/motherboards/s/compaq-prolinea-4-66

So far as I remember the board number is 197023-001 for the motherboard. I have also heard the stories of some having the same slot, but different needs or bios I guess.

With this being a shining example, meby someone or sander will conjure you up something that will work.

Small update. I've been working on some BIOS patches. Never change too many things at once 😉 Changing the cache wait state from 1 to 0 is a no go, this produces a memory error at startup.

Running the machine with more cache seems to be working well, and is really easy to do. It does need a BIOS modification though. But I'm definitely going to add a jumper block to the final design.

1MB modification takes two wires, 512KB cache takes only one wire:

Running the machine with 512KB cache and a modded bios:

So L2 is running at 3-2-2-2?
- have you tried lower fsb when playing with L2 timings? Makes me wonder what will happen in PROLINEA MT in 50MHz mode.
- is that with those bodge wires on the back or without? they are bad for signal integrity, ideally should be grounded micro coax 😁
- do you have access to a scope to look at eye diagrams? 😀 maybe those series resistors were doing heavy lifting cleaning signals in original module IF original module can run with 0 waitstates in the first place.
- also scope supply right on each chip, you could try experimenting with bodging more decoupling caps

In theory 2-1-1-1 should be in reach with brand new legit 12ns chips, but even as is its a 2x memory BW bump.

sander wrote on 2024-10-07, 08:25:

Small update. I've been working on some BIOS patches. Never change too many things at once ;-) Changing the cache wait state fro […]
Show full quote

Small update. I've been working on some BIOS patches. Never change too many things at once 😉 Changing the cache wait state from 1 to 0 is a no go, this produces a memory error at startup.

Running the machine with more cache seems to be working well, and is really easy to do. It does need a BIOS modification though. But I'm definitely going to add a jumper block to the final design.

1MB modification takes two wires, 512KB cache takes only one wire:

The attachment IMG_20241002_140247.jpg is no longer available

Running the machine with 512KB cache and a modded bios:

The attachment IMG_20241007_101556.jpg is no longer available

Ha! That's wonderful since I loved having large cache through.

1MB would be fun to find out.

Cheers,

Well it always takes time and fiddling to make things like this work.
And if it only takes a wire or two, I could even do that..
Also when I get one, I will test it on both boards. The presario 833 and the prolinea mt one, and see what it says and does. Probably nothing, but it's not like I have a deep understanding of bios, memory addresses and controllers.. I'm just working on excitment... 🤣