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SD HxC strange problems

Started by Optimus, 14:21, 10 December 13

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Optimus

I have the SD HxC floppy emulator Rev C. Used to work great in my CPC back in Greece. Even last time I tried it before I took it with me.Here, I have bought another CPC and I have noticed some problems. I don't if during the transfer I broke it or something starts to fail or it's a matter of the CPC.
When I run some stuff, most of them works but some of them might crash or run with broken gfx or music, as if 1 out of 10 a random corruption during the loading happens.
At first I thought it's the loaders used, since I was trying to run Batman Forever and other demos using a loader (those crashed immediately) but then even my own demos that use the AMSDOS loader fail.
Smaller demos like 4ks load and play fine. Smaller games play fine. I don't know if it depends on whether the demos are trying to load in the extra 64k (Star Sabre 128k played and then crashed near the end boss). Don't know if it's problem of HxC failing, or the CPC I have here has a corrupted upper memory block. Will try finding a disk drive soon and try with this to exclude CPC being faulty, then maybe carry the HxC to Greece in holiday to try with my other CPC there. Seems strange, cause last time it worked fine there.


Anyway, did anyone had a similar problem like this? Or maybe has a suggestion?


Bryce

How is the HxC connected to your CPC? It might just be dirt on the contacts that are causing some bits to flip?

Bryce.

Optimus

It was a 3.5" disk cable soldered with two switches that I bought some time ago. Maybe I should check, I hope it's something as simple as that.

gerald


The disk format have CRC in sector ID and data. So, unless you use a custom reader, AMSDOS should not load a sector where CRC is wrong and end up with the Ignore/Retry/Cancel question.

I would therfore check the memory of the CPC. But this can also be a Z80 problem (bad contact somewhere)

TFM

Other CRTC type?


Else you may like to run this...


Check Expansion RAM




It will check your RAM faithfully.

TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

robcfg

Be sure you don't have too many things connected at the same time.


Mine was not even booting, took away a couple of psu's, and suddenly it started working again!


Yes, I know, I should get a better electrical installation...  :P

Optimus

Quote from: TFM on 17:23, 10 December 13
Else you may like to run this...


Check Expansion RAM


It will check your RAM faithfully.




You were right! The memory is busted!


First 64k is fine. Then I guess it switches each bank to &4000 and finds mistakes in patterns, 4100, 417E, 4300, 437E, 4500, etc.. always this pattern till the end for both the 1st and 3rd memory bank it tries (the rest are ok). I guess the CPC was always fine for the vast majority of 64k games but not everything else using the 128k memory, owner maybe never knew it's busted. This means one thing, I am gonna carry my old CPC back from holidays :P

TFM

Sad to hear. At least you know what's the problem (i guess). Maybe you can replace the RAM chips? Good luck!
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

Gryzor

TFM is right, why not replace the memory chips?

Optimus

Are they easily removed? Need to unsolder? Or just to carefully pull out of socket?
And where can I find new memories? Or just get them from a broken CPC?
I'll also have to identify which ones to remove, but I don't think that will be hard.

Bryce

They are soldered in. You'd need to remove them and replace them with sockets, then insert new good RAMs.
If you want it done you could send me the PCB.

Bryce.

TFM

Quote from: Bryce on 10:31, 11 December 13
They are soldered in. You'd need to remove them and replace them with sockets, then insert new good RAMs.
If you want it done you could send me the PCB.

Bryce.


That can be done more easy. Just cut one pin (+5V or GND IIRC) of the old chip, and solder the new RAM chips over them. Don't you think that will work too? Even it this solution is not beautiful.
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

Bryce

Quote from: TFM on 17:48, 11 December 13

That can be done more easy. Just cut one pin (+5V or GND IIRC) of the old chip, and solder the new RAM chips over them. Don't you think that will work too? Even it this solution is not beautiful.

Yes, technically it works, but it looks shit and means even more work if one of the replacements fails. Better to do it properly the first time.

Bryce.

TFM

This depends if you're home or somewhere else. Sometimes you just don't have all your tools with you and may be lucky to borrow a soldering iron at all.

TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

MacDeath

#14
if it is just an issue with the extra RAM banks (extra 64k from a 6128), then just get an external RAM expansion, like the soon to come one from TotO...


This would certainly be easier than to find the proper chip to solder on the motherboard (and then no need to unsolder previous ones)


otherwise, you can cannibalize some other CPc motherboard that would be faulty anyway but I don't think those old chips like to be unsoldered ad resoldered after 25-30 years of existence.


Also : lead poisoning from those old electronic devices... :D


As any external extraRAM simply replace the internal extra 64k from the 6128.
I wished it wasn't the case so a +512K would make it a 640K... like my good old EGA 286AT PC (thx misteur Gates, you claimed there is no need for more than 640k on a PC and limited MS-DOS that way...)

Bryce

I don't think that would work. The software will still try to use the broken internal Bank before it uses the external banks.

Bryce.

gerald

Quote from: Bryce on 09:22, 13 December 13
I don't think that would work. The software will still try to use the broken internal Bank before it uses the external banks.
The 64k/256k  DkTronic's expansion override the internal 6128 expansion, as does my 512k one. A 6128 + 256k only has 320k, like a 464 + 256k.
The only one that will not is the 256k silicon disk which is mapped on the 2nd half of the official expansion range.
Therefore, an external expansion (except the Silicon disk) should fix the problem.

Bryce

Oh, I thought it was one of the extended 64K banks that got ignored / wasn't used on a 6128. Have you released the schematics of your 512K expansion?

Bryce.

gerald

Quote from: Bryce on 09:35, 13 December 13
Have you released the schematics of your 512K expansion?
The schematic won't help that much, as all is in a PLD  ;)
The current implementation uses an obsolete PLD and I am planning to change that. I am therefore not keen on releasing yet.


Bryce

Still sounds good. Let us know when the schematics and code are released. My own design (using standard 74xx) never got released due to lack of time. I am hoping to make it fully &C1 and &C3 compatible with a minimum of parts (without using a CPLD or GAL).

Bryce.

TFM

Quote from: MacDeath on 01:29, 13 December 13
if it is just an issue with the extra RAM banks (extra 64k from a 6128), then just get an external RAM expansion, like the soon to come one from TotO...


That is an excellent idea!!! External has always higher priority than the internal RAM. So adding an external RAM expansion (even as small as 64 KB) would deactivate the broken internal RAM chips!


MacDeath equ Genius
TFM of FutureSoft
Also visit the CPC and Plus users favorite OS: FutureOS - The Revolution on CPC6128 and 6128Plus

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