Got amstrad pcw 8256 but the fun don't lasted very long ...... :O

[JonB]

Quick update:


I acquired a bunch of STKs from ebay and resurrected the 8256 immediately. Now, the 9512 needs some other bits - C5006, C5007 & C5012 are replaced, and I am looking at Q5001, a D1207 transistor. I removed it from the board and did some tests with a meter that indicated something amiss, so I ordered one of those too. The only other parts around the STK that I would be concerned about are the diodes (normal and zener) but I can't seem to find them for sale. I will replace Q5001 and try it (as I have 2 spare STKs in case the new one I fitted gets fried like the one I took from the 8256)!


@Sebastian, if you're reading this, sorry for hijacking the thread. I think we have the same (or a similar) problem with our PCW power supplies, and I am hoping I can fix mine, then you can do the same. With a bit of luck we may get both of them running again.

[JonB]

OK installed the new one and surprise ... 310v between pins 1 and 14 so another dead STK 
All the other pins got almost 0v

Sebastian, it seems that this is normal. At least, the 315V rail is connected directly to pins 14/15 via the transformer. See the image I attached to the post below, it shows the circuit path. So maybe your STK isn't dead yet...


(edit: ..and if you look at the page immediately before the monitor schematic in the service manual, it says test point 10, which is connected directly to pins 14/15 of the STK, should have a waveform with a peak-peak voltage of 560v!)


Cheers
JonB


(Credit to jts1957 of http://www.tv-forums.com/ for the image.)

[Bryce]

Give us real part numbers instead schematic numbers, then I (we) can check if we have spares we could send you. Q5001 means nothing, 2SD1207 means a lot.

Bryce.

[JonB]

Sure thing-


D5005, 5007 : RD3.6FB
D5006, 5008 : DFC10E-KB4


These are in the parts list on page 32 of the tech manual (and on the schematic). Problem is, I searched for "RD3.6FB" but no exact match.. Same with DFC10E or DFC10E-KB4.


Cheers
JonB


PS, as you can see, I am hoping Sebastian's (OP) PCW has the same fault. Sure looks the same... from what he's said..

[Sebastian Blanco]

Dont´t worry about hihacking the thread i have given up on this, i have checked every component on the board and cannot find the fault, also show it up to some old tv technicians and them don´t seem to know what is failing i got pointed to try to change the flyback transformer but look like a hard to find part and a long shoot  .
But but but but ... like Jeff Goldblum could say found this thingy shematic:

on this forum:
http://www.vcfed.org/forum/showthread.php?55909-Amstrad-Schneider-PCW-IDE-drivers-an-interface/page2
Seem very easy to do, and for power i can just rig an atx power supply, and get rid of the monitor part, somebody have experience or information about this "video out mod" ? 

[JonB]

I should do, it's my layout... 


I use it on my PCW9512 along with a cheap hard disk power supply. You don't need one of those clunky ATx supplies for this. Let me take some photos and I'll show you.

[JonB]

OK Sebastien..


Power supply.


[attach=2]


This is a really cheap hard disk power supply, like this one http://www.ebay.co.uk/itm/191770678303 . It supplies 12v and 5v to the PCW. The PCW printer will not work with this, because it needs 24v. CCheck the connections on the 8256 before connecting it, you do not want to plug the 12v line into the 5v rail on the board...

[JonB]

Now the video adapter. You already have the layout. Here's the schematic.


[attach=4]


This is not my design, I grabbed it from another Amstrad web site. I do take some credit for the strip board layout and diagram which you already posted, though.


Top of the board.


[attach=2]


Bottom of board.


[attach=3]

[JonB]

You might also need the riser adapter, which is a bit of a hack. Its purpose is to lift the video adapter up a bit so that it doesn't foul any parts on the main board. If you choose to wire the video adapter to teh mainboard with a ribbon cable, then you don't need this.


[attach=2]


Wire the board and connect ground, green and composite video to the SCART plug. Make sure you use shielded cable for the green / composite lines and connect the shield of both to ground. You can use a probe clip to connect the 5v line of the PCW power socket to the +5v line on the adapter board. No need to worry about 0v (GND) because it's on the main board's video plug. Now plug the video board into the main board's video socket, like this:


[attach=3]


Connect the SCART plug to the TV and turn on. You may need to adjust the trimmer VR1 to get the right brightness.

[Sebastian Blanco]

What a surprise JonB such a small world indeed  .
Very nice board schematic must say, thank you for the information and the pictures i will build the board this week and test on.
My plan is to install the board on a prototype plastic box drop a pair of modded 3.5 floppy drives and live the good life.

[JonB]

Leave some space in the the box for the IDE interface..


http://www.cpcwiki.eu/forum/nc100-nc200-pcw-pda600/who-wants-ide-drives-on-the-pcw/

[Sebastian Blanco]

  cool do you already finished the design ?.
where i can get the pcb

[JonB]

uIDE report

   
• Driver suite complete (works under CP/M Plus and Locoscript). Does not support cold boot.
• Prototype Mk 2 built and in testing. Current design uses just 2 ICs.
• uIDE PCB layout complete, but may be altered if testing indicates problems.
• Z80 shim card / PCW expansion port adapter not yet designed. You need to use one of these to connect the uIDE card to the PCW. Choose the Z80 shim if you want to mount the uIDE internally and your Z80 is socketed, otherwise choose the expansion port adapter (this will need a 50 way IDC edge connector - 50 way IDC header ribbon cable, which will cost more).

[Gryzor]

Public service token: here's a "μ" you can use to copy/paste and do it properly instead of using a 'u'

[Bryce]

It's a standard symbol on almost all keyboards: AltGr + m

Bryce.

[Gryzor]

Oh, let's see: 


Hm, nothing for me, at least with US English set up at the office PC.

[robcfg]

I have Windows in english with a Spanish keyboard and that doesn't work either.


I wish it worked, though!

[Bryce]

Strange, I have a German keyboard here and an English one at home and both work. The Lenovo Keyboard here even has the symbol printed on the keyboard key:

http://www.notebookcheck.net/fileadmin/_processed_/csm_Lenovo_Ideapad_Flex_10__12__2ee1d1bece.jpg

Bryce.

[Gryzor]

Huh, interesting, indeed it does!! Of course there's also Alt+0230, but you need a numerical kb to easily use it.

[remax]

In France, it's directly accessible with SHIFT+*

[Gryzor]

Strange, the choices made on international keyboards...

[JonB]

Public service token: here's a "μ" you can use to copy/paste and do it properly instead of using a 'u'

"μ" normally means "micro", as in μF ("micro Farad"), but the "u" in "uIDE" means "Universal".

[JonB]

Keeping it on topic for a moment. This won't be much help to Sebastien, but I managed to get my hands on a partially working power / CRT board for the 9512, so I might be back in business at some point soon. I would have liked to have fixed my board, but it is beyond my abilities. I even tried calling TV repair shops on the basis that the PCW's monitor is just like a TVs, but no one was interested...

[Gryzor]

"μ" normally means "micro", as in μF ("micro Farad"), but the "u" in "uIDE" means "Universal".

Ohhh my bad then, thanks for pointing it out

[Bryce]

Keeping it on topic for a moment. This won't be much help to Sebastien, but I managed to get my hands on a partially working power / CRT board for the 9512, so I might be back in business at some point soon. I would have liked to have fixed my board, but it is beyond my abilities. I even tried calling TV repair shops on the basis that the PCW's monitor is just like a TVs, but no one was interested...

There's still TV repair shops in existance near you?? Wow! 

Bryce.