A2620 roms >= v6.6

[tiim]

Hello,

I finally, after 25 years, got my hands on a A2620 '020 accelerator for my Kickstart 2.x A2000

I remember, back in the early 90's when I bought my first 020 on the consignment rack, I had to take it back to my Amiga dealer, and then they sold me upgraded ROMs for it... How happy I was to use Vistapro on that old board!!!

Anyway, here I am again, except there are no shops nearby

I have seen updated versions posted to the Zone now and then, but ATM, there are none there.

Would one of you kind Amigans post V6.6 or higher to the Zone? I need HI and LO of course.

Thank You in advance!

[Jope]

Get them from Rainer Benda's website.

http://www.rbenda.de/commodore/soft3-2.html

[tiim]

Thanks Jope.

Unfortunately, after burning V7, I get a black screen. Either something is wrong with the board, or the A2000 mobo. Machine boots fine without 020 card in there. Probably got a bad board and paid too much... Hopefully I 'll find another someday.

Thanks again,

Tim

[alexh]

Are you sure you had the EEPROMs in the correct sockets? You'll get a black screen if you've got them the wrong way around.

Second source your EPROM files, check against CRC32/MD5?

[tiim]

Alexh,

Sockets are indeed correct. I don't have another ROM source, and I am not keen enough to check CRC, but I'll look this up and give it a try. Thanks for your advice. I am not giving up just yet

[Toni Wilen]

expansion_boot_roms in the zone includes A26x0 ROMs.

[tiim]

Thanks Toni.

There appears to be separate 2620 and 2630 ROMS. I'll give the 2620 ones a go. I am assuming the later date ones are version 7. No way for me to tell in my programmer buffer.

Alexh, I tried swapping U4 and U5, and I did manage to do a CRC check and the two sources I had were the same CRC. Same black screen. The files on the Zone, at least the ones labeled A2620 have a different CRC, here we go!

Cheers

[tiim]

Eh, no love for me

I'll have to buy another CPU accelerator to check if it is the Amiga motherboard, or the accelerator board.

I might take my A500 apart and try the Kickstart 1.3 in my A2000 as well.

Sad Day

[tiim]

I noticed that my original boot ROM stickers had this to say:
390282-06 DAFA LO
390283-06 701F HI

Is the "DAFA" and "701F" a checksum? I load these rom files into a checksum calculator and CRC-16 gives me four character spaces, but no matches.

Also, Am I correct, the A2630 boot ROM code is used on the A2620 on later revisions of the boot ROM code?

I see on the Amiga HW database that rev 7 has the following four character identifiers for the A2620:
LO: 66DA
HI: D1D3

I can't match these, either. I must be using the wrong calculation. MD5 and CRC-32 give me longer identifiers.

Thanks

[Toni Wilen]

A2620 and A2630 labels in ROM files only mean if ROM was dumped from A2620 or A2630. All of them should be fully compatible with both CPUs.

Apparently there are few different CRC16 algorithms...

[tiim]

Thank you, Toni.

This has been a learning experience for sure.

I tried a KS1.3 ROM and the same black screen. I am going to re-inspect the motherboard under the microscope. There was zero battery leakage on my Rev 6.2, on the top at least.

I checked the PSU voltages for any sagging, and none were present. I need to learn tracing logic signals next!

Thanks

Tim

[mech]

Originally Posted by tiim

Thank you, Toni.

This has been a learning experience for sure.

I tried a KS1.3 ROM and the same black screen. I am going to re-inspect the motherboard under the microscope. There was zero battery leakage on my Rev 6.2, on the top at least.

I checked the PSU voltages for any sagging, and none were present. I need to learn tracing logic signals next!

Thanks

Tim

Quick and dirty thing you can try is swap Cias around,a bad cia can do black screen,but i would also investigate Agnus, bad contact in sockets is common in old boards. pull,check chip pins and socket pins and reseat all chips.

Ram can also fail.

[tiim]

Thanks Mech. The system boots and loads WB perfectly without the CPU slot occupied by my accelerator. Today, I am reviewing the A2000 service manual and MC68000 datasheets to get acquainted with what I can read on a logic probe or oscilloscope. Hopefully, signals that work with a bare 68000 can be detected with the "bad" 020 card installed to help me get to the issue. My guess is a bad PAL on the accelerator. Would be great to have a working A2620 to compare to. I'll keep searching for one!

[tiim]

UPDATE,

So, I found Dave Haynie's Archive.

Under the 2620 section there is an interesting discussion (2620_prb.txt) about trying to get the V7 ROMS to do anything with either Kickstart 1.3 or 2.04...

Darn, I wish I had my old A2000 still! It worked fine with the 2620 AND 2630 using KS 2.x

I had a Rev 6.5 motherboard in that thing, too...

anyway, looks like I'm going to do some hacking over the weekend. I'm not good at it, but I die hard

[B2k_ad]

Since you referred to you board revision.

Did you check that R1000 on your Mainboard is present and working?
It is present since Rev 4.3 or 4.2 and is just there for the 2620.
If it is however not working the 2620 would put the 68000 in 6800 controller mode and thats the end of the story.
R1000 should be near the 68000 on your board.
On rev 4.x it is near the RTC chip

[tiim]

Hello B2k_ad,

I have the resistor (R1000) on my Rev 6.2 board and it reads 470 ohms, which matches the color bands. There is absolutely zero acid leakage on the board (a miracle these days) and the battery has been removed and not yet replaced, so the RTC is not functioning properly. Not sure if the lack of a RTC has anything to do with the whole mess. I don't think so, since my machine boots up just fine (without A2620 installed) with the A2091 and SCSI2SD drive installed.

I think I have a bad chip on the 2620 card. I honestly have no clue where to begin looking. Possibly VCC and Reset lines with my logic probe is a good start. I have access to an oscilloscope if need be.

Thanks for the tip.

Tim

[B2k_ad]

I gone through the thread and i suspect you did evrything already.
May seems like a stupid/annoying question but....
Are all jumpers correct? and are they in good condition?
I had one mean Jumper fail on me.. it was an A500 ram expansion
simple as it was it would not run... only as i lost the jumper while trying around
i had to use a new one and the Problem was solved.
Did you try the 2620 with the fastram swtiched off?
An last but not least did you try the 2620 without the 2091?