Philips VG 8235/20 dead disk drive

Supporter (12)

05-02-2003, 22:22

My recently acquired MSX2 unit - a nice VG 8235 - hasn't got the original drive working . I'll tell you the symptoms and maybe you guys can help me out:
The FDD busy LED comes on while computers's booting (ok - fine).
-Disk Basic is loaded (suprise, suprise).
-FDD busy is now off (fine).
-I try a "files" command without any disk in the drive - it gives: Disk ofline. (fine.)
-I insert a 360kb ss disk from my MSX1 machine and type "files" again - the FDD busy turns on a little and the screen shows: Disk offline. (Humm strange I think - let's try formatting a disk)
Without any disk in the drive I type "call format" - It asks the drive, I say A - it gives "write protected". (I smell something...)
I insert a standard PC disk with a piece of tape on the HD hole and again "call format", A, - the FDD busy light comes on and *never* goes off - there is a low noise coming from the drive indicating some activity but nothing like a format noise (whatever that is actually). - I have to reset the computer...

I smell a dead drive here - what do you say?

Time to attach a standard PC drive in. I believe this is possible? Will I be able to use 720kb disks? How is this done exactly? I just switch in the drive and it get's working? I believe I'll have to fiddle with some connections right? I am unfortunately no electro expert so any "verbose" help would be very welcome.

Thanks for your time and patience.

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Van mars2000you

Enlighted (6097)

05-02-2003, 22:40

You can find useful technish solutions on the following sites :

http://www.msxhans.msx2.com/
(go to the hardware section)

http://www.geocities.com/Yosemite/Meadows/7278/MSXKIT/INDICE.HTM

It seems that you must first convert your VG8235 drive into a NMS8245 drive by replacing an Eprom before to install a 720 KB PC drive

Van LaFey

Supporter (12)

05-02-2003, 22:51

It seems that you must first convert your VG8235 drive into a NMS8245 drive by replacing an Eprom before to install a 720 KB PC drive

The EPROM changing is the trouble... I didn't think this was needed...

Seems like I'll have a lame msx... Is there any hope of at least getting the drive fixed?

Van Grauw

Ascended (10308)

06-02-2003, 00:50

Eprom change isn't very difficult. As far as I know the disk ROM is located in a socket, so it can easily be taken out. Then you can simply order a new disk(EP)ROM from someone in your neighbourhood with an EPROM programmer. I know Bas Kornalijnslijper has them, I saw he brought a whole batch of them to the Oss fair. I suggest if you live in Spain, try asking Padial, if you live in Brazil, ask Ademir.

http://www.hansoranje.demon.nl/ (our other Dutch MSX hardware repairman ^_^) also has instructions. They seem to be in Dutch only though.

~Grauw

Van LaFey

Supporter (12)

06-02-2003, 02:45

Hehehe - actually you missed me by close - I'm in Portugal. Unfortunately I don't know anyone here into MSX... I do know Baas Kornalijnslijper - he's a great guy - I have some items bought from him - maybe I ask him about the EPROM.

Van pitpan

Prophet (3145)

06-02-2003, 09:41

Yes. Definetly you have to change that diskdrive (probably the only problem is the rubber belt, substitute it). Anyway, I suggest you to install a PC disk drive (High density will work fine).
You do not need to change the EEPROM to work with it, but it will only work (as the original VG-8235) with 360 KB formated disks (single sided). To adapt the connector, just visit www.aamsx.org and have a look there, they have got an excellent tutorial about how to build your own cable.
After that, just decide if you want to use single sided disks or double sided (replace the EEPROM).
I have one VG-8235, and I have just changed the disk drive but not the BIOS. I made the same process with two NMS-8245, and they work great and are less noisy than the original disk drive.

Kind regards,

Van LaFey

Supporter (12)

06-02-2003, 11:29

I'll try and swich the drive then. I already contacted Bas on the EPROM issue so I guess I can always upgrade it later on with the new drive already fitted.

I heard drive belts are indeed prone to malfunctions - sadly I don't have much time to track down the correct type - and more so because I don't know if that would fix the drive. Better to just fit in a new one and keep the old one for later assessment.

I'll keep you posted on details.

Van Grauw

Ascended (10308)

06-02-2003, 16:33

Getting support for 720kB disks is really worth the trouble. If you're gonna replace the 360k drive with one which supports 720 anyways, you might aswell replace the ROM. It's not really expensive and easy to do. And it'll make a lot of cool stuff work, you can play SD Snatcher for example, and a lot of Microcabin games. The number of games on 360kB disks is quite limited, although most cracked disk versions of ROM games will fit on it. And uh Portugal eh? Well that's close to Spain, so I'd say you contact Padial, but well, I guess you can contact Bas just as well.

~Grauw

Van LaFey

Supporter (12)

07-02-2003, 04:59

I compiled the following connections for a 14 to 34 pin disk drive. Philips VG8235/20 - PC Disk Drive (standard). Check it out - I couldn't find clear info about this model but it was easy to extrapolate using service manuals and the webpages on this topic.

Check the preliminar conclusions I got at: http://pwp.netcabo.pt/lafey/vg8235_drive.htm

I am not partucularly sure about the 7 - 11 pin connection - so please shoot up some thoughts.

(I bought a nice *black* TEAC disk drive to fit in the MSX - :) )

Van msxhans

Expert (77)

16-02-2003, 11:23

And? Does it work?

If so, please write down how you did it for others!

Van Leo

Paragon (1236)

16-02-2003, 13:36

Well I have also a VG8235 which 360Kdrive does not seem to work anymore ( or not so great as last month ) , I have also a sunrise-ide interface .

I wonder if I remove the Diskrom of the msx then the sunrise interface can handle the drive directly.It may have only routines to handle hardisk , but i guess that the original dos2 bios should have since computers like TRs have only dos2 bios, they dont need dos1+ dos2.

It should be possible to update diskrom only with sunrise flash rom ( which is more convinient than replacing the eprom when you dont have a burner )