nms8245 slot1 is not working anymore

Expert (80)

25-03-2016, 14:24

my msx8245 slot 1 is not working anymore are there any tips i can check.
It is not the connector itself. (To left the cleaning apart aside)
Slot 2 is working fine.

I also tried to connect the clock pin of the slot to the z80 direct so see if the 74ls04 is broken. no result.
I also took another slot select for slot 1 and was also not working.
i also checked the + and - on slot1 and all is there.
does not start any cartridge. tried games no startup. tried fmpak with command _fmpak, no result (working in slot2)
Anyone has any ideas thank you.
(im dutch but i assumed we write in english overhere lol)

Por enribar

Paragon (1224)

25-03-2016, 17:41

Same trouble happened to me many years ago...
I asked in several forums but nobody knows the solution...
Maybe the problem is under the slot -> a lost connection to the mainboard (or the mainboard itself, or some burned slot-controller chip...).

Por spacegremlin

Expert (80)

25-03-2016, 19:29

i agree with what you say. but.
they also say to make a internal 3rd primair slot. you can use all the same connection.
and only change the slot pin to the 3rd primair slot. this indicates to me. that the rest of the pins are.
connected to each other. with other words at the end they come from the same chip output.

If that is so. i would assume that slot 2 would also not working, but that is working fine.

i will resolder the connection from slot 1 first to see what happens.

Por usuario_msx2

Paladin (763)

25-03-2016, 22:32

If slot2 is working Fine,
Try to change sltsl1 instead of sltsl2 in slot2
if cartridges works fine in slot2 with this change you will
be sure that sltsl1 is ok.
And fix the problem will be
possible using for example a spare part cartridge slot from
Philips 82xx (from Bas if available). How do it?
image:
https://m.flickr.com/photos/44218601@N06/4598431599/

Putting a wire from sltsl1 to pin 5 of slot2 (not used)
then in the 82xx cartridge side a wire from pin 5 to pin 4 of slot2
all signals will be ok .
good luck

Por spacegremlin

Expert (80)

25-03-2016, 22:39

thats indead i try. to test the sltsl1 on the second slot.
but i tried the sltsl2 on slot1 so the other way around.
that didnt work, so i can assume the sltsl are okey. or am i wrong.

i will try your tips again. to rule out some other things.

Por usuario_msx2

Paladin (763)

25-03-2016, 22:40

If sltsl1 replace sltsl2 and your cartridges
works in slot2. Hoy could fix the problem very
easy in the way I say in my last post.
You can see this solution in the link
You must use all signals from slot2 and add the sltsl1 signal.

Por spacegremlin

Expert (80)

25-03-2016, 22:41

yes i understand, i will check it. but even so if i found the problem i want to fix it on the board itself. not external.
if correct you can only use one cartridge on sltsl2 or can you run more cartridges on that.?

btw need flashreader, is that msx , or pc converted?

Por usuario_msx2

Paladin (763)

25-03-2016, 22:53

If you do it. You will have 2 external slot1 and slot2
It is a 8245 with internal slot2 expander

Por spacegremlin

Expert (80)

25-03-2016, 22:58

yes i understand thank you.
i want to fix the internal slot.

But i hope first i find the issue. then i can see what i will do.

If the internal works again, then the external is always an option afcourse.
and if the internal slot will not ever work, i will strip the nm8245.

Por spacegremlin

Expert (80)

27-03-2016, 00:26

I have order some chips wich 1 i think could be the problem but not sure.
I also order a ic socket for the z80 to replace the z80. Only problem is, that i have a upgrade on the z80 for the extra memory so i am not sure if i would replace that.

Afcourse the problem could be in the main enige but there are some addition options to get around that.
For now i will replace this and see what happens.

Like you say its not the first time this happens, so i really would like to find out what is wrong.

greetings.