SD512 with HB201P stucks | MSX Resource Center (Page 3/5)

Hero (516)

24-08-2018, 13:09

It seems that the SD512 firmware is not working. The problem could be a defective/dirty slot or damaged firmware of the SD512 or maybe the IC8 ROM chip is still causing problems.

Have you tried both slots? Have you tested the PAUSE button (be sure that the machine is not paused)?
Also try to switch off the RAM (expanded slots) of the SD512 and see if something changes.

By odaman68000

Rookie (25)

24-08-2018, 13:29

Pentarou wrote:

If you think that's the problem just clean the contacts.

I think so too and I already cleaned the contacts many times.
But cleaning is not a problem.
The problem is very poor contacts quality.

I can't express very well in my poor English skill (I'm from Japan, and of course I'm native Japanese speaker),
the scratch and the scratch, and the scratch on surface of contacts, these increases insert/de-insert SD512 from slot.
Very poor contacts...

By Lao Mu

Supporter (13)

24-08-2018, 17:14

Pentarou wrote:

It seems that the SD512 firmware is not working. The problem could be a defective/dirty slot or damaged firmware of the SD512 or maybe the IC8 ROM chip is still causing problems.

I think the slot's and the contacts are ok. I will take the IC8 completely out. But 1st I need to buy a socket to put it
in the empty IC slot. On this way i can put the ROM back if needed with some of this PIN<>PIN rails.

Have you tried both slots? Have you tested the PAUSE button (be sure that the machine is not paused)?
Also try to switch off the RAM (expanded slots) of the SD512 and see if something changes.

Yes I tried that all in all different states of the switches and the ROM slots. It is always the same failure: The Maschine stucks in the Welcome-screen "MSX System Version 1.0" Thsi makes the SD512 now most suspect.

I send a mail to 8bit and ask them for some support. At least I still have warrenty.
But of course i want to prevent from send back return horror. Do you know a possibilty to read & flash the SD512?

By Pentarou

Hero (516)

24-08-2018, 22:36

The SD512 can be (easily) re-flashed, but there are a couple of problems with your setup:
1) The tool (sdmupd.com) is a MSX DOS command, and the ROM file is 128KB, so your current machine can't do that.
2) You have to be able to access the DOS prompt, if the cart seizes the machine you can't do much.

To read the flash you will have to boot at least into basic, then you can try some utility as odaman68000 suggested.

By Pentarou

Hero (516)

25-08-2018, 01:02

odaman68000: Can you write what pin number did you cut exactly? In a previous message you wrote pin CS (pin 27) but then I'd like to know if you also connected it to GND via a resistor. Please explain clearly.

I'm asking this because there are conflicting info between the schematic, the datasheet of that PROM, and what you did.

Also when the SD512 boots, what is the version number of the Nextor Driver? Is it 1.0.4 or something else?

By odaman68000

Rookie (25)

25-08-2018, 05:07

Pentarou wrote:

odaman68000: Can you write what pin number did you cut exactly? In a previous message you wrote pin CS (pin 27) but then I'd like to know if you also connected it to GND via a resistor. Please explain clearly.

I examined my modification today.
The firmware ROM chip is OKI M38128.
Originally, firmware ROM chip pin 27 (CS) is +5V pullupped with 22ohm register. (J1 jumper is closed with 22ohm)
In my modification is, cut this line and pulldowned to GND with same register (22ohm).
Is there any mistakes...? Mmmm, CS is negative logic?
Originally it is pulluped with +5V, so I thought GND pulldown will disable this chip.
Other ROM cartriges works well, only SD512 has problem.

And caution, my HB-101 is "japanese version". So RAM is 16KB, and there's NOT J2, J4, J5.
There are some difference from HB-201P schematics. (HB-201P is euro version of HB-101/201, euro HB-101 has 32KB RAM)
The pin 20 (CE) and 22 (OE) are connected, but I can not examine well because pattern lines goes under ROM chip...
But maybe CE is connected to SLTSL3, OE is connected CS1.

Pentarou wrote:

Also when the SD512 boots, what is the version number of the Nextor Driver? Is it 1.0.4 or something else?

It's displayed as "104" for Nextor driver version. I think it means 1.0.4.

By odaman68000

Rookie (25)

25-08-2018, 06:26

Hi, it's me again.

I tried other configuration, and I got same result as before.
1. At first, I repaired HB-101 as original. (+5V -> pin 27).
2. Cut the pattern line on pin 20 and 22.
3. Connect +5V to both pin 20 and 22. (so, ROM data pin should goes high impedance state)

I have no idea why "pin 27 -> GND" modification had disabled ROM chip.
And I found the M38128's data sheet on the internet, and this data sheet says "OE and CS active level is freely selected".
ftp://bitsavers.informatik.uni-stuttgart.de/components/oki/_...

Can it be any hints?

By Pentarou

Hero (516)

25-08-2018, 15:18

I was going to suggest to Lau Mu to try the same modification as you did, but I don't know if will change anything.
The masked ROM chips seem to use different enable levels, moreover there are many versions of that motherboards and available schematics aren't universal.

By Lao Mu

Supporter (13)

26-08-2018, 20:23

Hi,

I just plug solder out the IC8 complete and put a socket inside then I tried this:
https://msx.pics/image/ULC4g :)

With SD card it does not work, but I think this is a partition or setup problem. Also somtimes it will not
start ...then I have to clean and align the slots again.
By the way, as Odaman68000 said. The cartridge slots are really very poor. I decide to replace them.
I already found a source. The original are from Mitsumi, but one can use EDAC 345-050-520-2 02 instead
They are green then...but I don't care.
I also found that the 5V from PSU is only 4,47 V (At PSU). This could also be a reason for instability.#
I will replace EL capacitors from PSU also.

:) Not yet finished but a step further.

Thx for all help and hints...

By Pentarou

Hero (516)

26-08-2018, 23:16

So you removed the chip? But why the socket?

For your boot problem:
Nextor needs 128Kb, so the switches have to be in the Mapper position, otherwise it will boot in disk basic.
If it still doesn't work, try to format the SD card in the MSX with this procedure:
When you boot keep the "1" key pressed until you get to the basic prompt, then use "call fdisk".
Then move the SD card to a PC and copy the files.