Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Munchkin on June 06, 2020, 12:27:51 AM
-
Last year I recapped my rev 5 A500 and replaced the original PSU with a Meanwell one. I replaced the Agnus and converted it to 1MB chip way back in the early 90's. It also havs an
It works just wonderful as it is. If I connect my GVP SCIS controller it works just fine as well. (Kinda weird that the original 120MB Quantum drive from 1992 is still working since it's been in storage for 20 years)
However. I've had a VXL-30 with it's RAM-32 board in it that worked fairly well. Also had 4MB ram on the harddrive controller, and it worked even if as I'm told nowadays it shouldn't have.
I've concluded that something's wrong with the memory of the Ram-32 board. I get memory errors and the system freezes or crashes quite quickly. So, I removed the accelerator and put the 68000 back.
Next problem is. I cannot have any memory sticks in the GVP controller. It just won't boot if I do, even if I set the jumpers correctly. Only way to get the system running is to have no memory on it at all, which leaves me with 1MB chipram. Then the system is rock solid but I can't do very much with it with only 1 MB ram.
So. Either those old 30 pin 1 MB ram sticks are all faulty or something is wrong with the GVP controller.
With no memory in the controller and only the 68000 installed the system runs absolutely rock solid.
Don't really know where to go from here.
I would love to find an accelerator to replace the VXL with. I prefer it to be an internal one because I want to continue to use the GVP controller as I have a Syquest and a SCSI CD-Rom that can connect to it.
I have a Vampire V2 on order but whenever that will happen, if ever, I don't know.
Suggestions?
-
The ram on the accelerator is 32-bit and the RAM on the GVP sidecar is 16-bit. You can use both simultaneously but you'll need to run a 3rd party "hack" early in your startup sequence to get it all to "play nice". I ran the same setup for years and had an A500 with 18MB of RAM (8MB 32-bit fast, 8MB 16-bit fast, 2MB chip). Even bought faster CPU & FPU and overclocked the VXL a bit. Could never find the correct PAL's to get it to support the 50MHz mode but I was able to give it a "bit of a bump" by trying different oscillators.
Like you my RAM-32 board eventually started to fail and the system will only boot if I disable it (by commenting out the third party tool in startup-sequence). The system runs like a dog with only 16-bit RAM and honestly I haven't had time to even turn it on in a couple years to mess with it. Maybe one of these days I'll hunt up an alternate internal accelerator to replace the VXL.
Sorry no real input on your questions, just popping by the forum for a sec and wanted to share since I have a very similar config to yours. Good luck!
-
You could jumper your GVP to different memory config and then test every memory sims individually. Have you checked that jumpers are right places? http://amiga.resource.cx/exp/impact500mk2
-
Yes, I've tried different configs. I have the manual for it so I know how to set it up. But, I think all 4 sims are dead, I might even have damaged one or two of them myself trying to take them out since they were really difficult to remove. There has to be at least two, not only one, so can't test them one by one. Which ever two I test with I get a board fault at bootup. Hunting for working 30 pin sims is probably futile these days. I know there are plenty on ebay but how many of those are scams?
Well. If I can get a replacement for the VXL with at least 4MB, preferably 8 or more, then the memory in the controller won't matter anyway. Never gonna do any heavier stuff on it, I have an A4000 for that.
If I run the controller without ram and the 500 without accelerator everything works just perfectly, but 1 MB chipram only is not fun at all.
-
Just my 2 cents here but i would guess the memory controller has gone bad(likely PAL chip(s)) since its unlikely all 4 simms would fail at the same time.
30 pin memory is dirt cheap still,so you could take a chance and buy more simms.
-
It worked when I put it in storage over 20 years ago. Then when I took it out it just wouldn't work properly. At first I recapped the 500 and replaced the PSU. Still no go.
Well, maybe I should get a diagrom to test all parts on the motherboard. Using Systest 1.2 (that's the one I have on the harddrive at the moment) reveals no issues though. Have no way to get a newer version to the 500 right now since my A4000 is taken apart to be restored and no floppy on any of my PC's.
I have reseated all socketed chips, except for Agnus (8372A) since I'm a bit worried that the socket might break, it is 32 years old after all.
I think I made one mistake when I took it out of storage. I should have cleaned everything properly and reseated everything before trying to start it up. But hindsight is always easy.
-
might be worth checking the PSU from the HD8+ that you're getting a stable 5 volts.
My HD8+ had cap squeal from the PSU for ages, but seemed to be working, then the squealing got slowly more noticeable and eventually the PSU gave out over the course of a year or two getting more and more unstable.
I got some PC molex power extension leads and butchered up a feed from the A500's internal floppy power port to run externally to feed the GVP HD8+
I'd also pulled out the HD8+'s original 52Meg drive, and swapped in a compact flash solution to - as far as i could figure - reduce the power requirements.
turned out to be a blessing when my A530 arrived as it didn't turn up with a PSU.
-
Been thinking about that actually. Though, with no ram in it and no accelerator in the 500 everything runs rock solid. No memory errors with the onboard and memory expansion on the 500.
Did replace my A500 PSU with one from Meanwell just after I took it out of storage as well.
-
If you convert the GVP sidecar to use a CF or SD type drive you can do the "hack" to get it to run off the A500's internal power supply. You can remove the internal fan as well if you do this. This might be an alternative to replacing the power supply, and as a bonus there will be one less bulky adapter sitting on your desk. ;)
http://members.iinet.net.au/~davem2/overclock/a500hd.html
-
True, it is really easy to convert it to get power from A500. Could day that HD8+ has build in support for it.
http://members.iinet.net.au/~davem2/overclock/a500hd.html
You can also get rid of fan, because old SCSI drives get really hot, SD2SCSI not.
-
Oh, this is perfect. Perhaps this wouldn't have worked with the original "heavy" 2.5A PSU but with the new Meanwell PSU it most certainly will.
Thanks for the tip.
I have external SCSI CD-Rom and Syquest drives but they have their own power supplies so I doubt that will be an issue.
If a v6 SCSI2SD will work well on this setup I'll certainly get one.
-
Another little bonus of switching to flashdrive is you can pop the card out, stick it in a reader on a modern machine and take a backup of your drive - or a restore just as easily. SCSI cards are not exactly a commodity these days! ;D
Plus you can "build" your machine in winuae before sticking it into "real hardware". but personally i'd build it all via an external gotek for the warm fuzzies of using a floppy drive.
i'm tempted to get another A500 just to plug my HD8+ back into. may even keep it stock OCS 1.2/1.3 for that time capsule feeling. 8)
where to put another machine though!
-
I know the feeling. I have 5 computers in this room now. C64, A500, A4000 and two Amdows machines. Also a simrig so there just isn't any more room. Need a huge house!
-
Had an A530T in the day (1993!) and recently got back into the A500 and a new/old HD8+ with all the associated frustrations.
In 1993 it seemed so much easier, but tbh the cpu accelerators I've tried all don't work with it.
The PiStorm kind of sort of does - but it's not a true amiga accelerator.
TF534 - nope
TF536 - nope
Cheap Polish 68K@36 MHz - nope
And I'm not going to pay over $500 for an old VXL or similar accelerator on ebay.
Frustrating as the SCSI2HD works great now in the HD8, but an unaccelerated A500 is painful.
Anyone have a modern cpu accelerator (in stock!) that works with it?
(what 'hack' were you referring to for 16bit/32bit memory ?)
-
It would be really difficult to find a accelerator wich would work with GVP HD8+, because it uses DMA.
-
A530T yummy ... Wouldn't be without mine. Anyhoo, biggest problem with the GVP sidecars is the power supplies. I have quite a few and the capacitors inside just ooze and die. So its worth checking if you have an original PSU. Also check the connector cus they can be a problem inserting and I've had them with damaged connectors, especially at the ends. And also worth getting a ground if you don't have one fitted. Poor connectivity can cause consiiderable issues and power.
https://www.scuzzscink.com/amiga/scuzzblog_december17_12/car_sbd_301217_09.jpg
Simply the best.
-
AHA! the Supra Turbo28 runs fine with the GVP HD8+, but it limits the ram to 4meg as it needs some of the addressing for its sram cache.
sure it's not 030 fast, but it's a 4x uptick on stock... that was my config - still able to hold it's own vs all my friends who got A1200's and then fast ram upgrades...
-
Hi,
I used the HD8+ and M-Tec030 with 4MB 32bit-ram (no DMA, no Autoconfig) - long time ago. :)
Try the following:
DMA: set DMA-Mask in RDB to 4FFFFE for every partition - DMA into 16bit-ram only and HD8+ should work with other turboboards