ChrisS is trying to build a H5C1

[Oldskool]

Hi Forum,

Just bought the MB and some parts from the webshop.
Put the stuff on the PCB.
Turned the power on and.......... stupid white screen :) :oops: :cry:

Is there 5V?
I measured about 4,8V at the floppy power connector so maybe too low?
This old PSU did power the donor STF

Is there a clock?
Yes I think so. It seems to be 16mhz at the out pin on the shifter

What did you try and are the ic's OK you used?
The CPU, ROM, RAM and MFP are bought from the webshop. The shifter, MMU and glue are straight from a working ST. The YMF and 6850 are from ebay as well as the WD. However I tried a different CPU, Shifter, MMU, Glue, DMA and YMF. This does not change the behaviour. I'm however not 100 % sure that the 6850 and WD are ok.

What behaviour does the computer show on screen?
With TOS jumper on I see a solid white screen no sound (static) no floppy activity (frozen state, reset button does not seem to do much)
With TOS jumper on and no RAM inserted I see a black screen surrounded by a white border. Reset button works (fully white screen after reset and than black again surrounded by white)
TOS jumper off shows random screens however the behaviour is certainly different than with the jumper on (reset does seem to work somewhat)

Insert an Atari test cartridge and tell me what you see?
Sorry don't have one yet.

Maybe you can spot my stupid mistake(s) and help me a bit it seems to almost work....

spotmistake.jpg

jumperyes.jpg

jumperno.jpg

5v.jpg

No RAM.jpg

16mhz.jpg

[exxos]

Try this first.

viewtopic.php?f=89&t=5600

[Oldskool]

Thanks for the help ordered the resistor (470 ohm) and put it in place like this.
Cleaner 32 and 16 mhz indeed (on my cheap scope).
However system is still behaving like post 1. So no boot yet.
What should I do next.

soldering.jpg

32mhz.jpg

16mhz2.jpg

[exxos]

Work though the troubleshooting steps.

viewtopic.php?f=78&t=2362

[exxos]

Also.. I think your sound IC is in backwards... ? Can't tell very well so only going on the IC you have on top.

snd.PNG

IMG_0661.JPG

[Oldskool]

The ym is OK in the socket.

[DoG]

It seems you have a TOS2.06/TOS1.04 chip. You can only run TOS v1.04 or below without a decoder. So the jumper must be set correct for it to boot. It will also take a while to boot if you have no floppy attach to the board. I would also adjust the voltage to 5V.

[PhilC]

Just a couple of observations.

The tos rom you have is 1.04 &. 2.06? If so then the H5 will only boot it 1.04 mode without the figment of a TOS decoder. So when you had the ram removed you had the rom jumper on and got a white screen with black foreground, I think that you need the rom jumper on for TOS 1.04.

Now doing diagnostics on the H5 is a lot easier if you use one of the expansion sockets rather than the PLCC CPU.

So check the pin out of the DIP 68000 and locate both the /RESET and /HALT pins, check that when you press the reset switch the reset pin goes low but then returns high (5ish volts). Check the same for the halt pin. Before pressing the reset is it high or low? If it’s high then great, does it do the same as the reset pin? If not then you may pick up a quick blip of high then the halt pin returns to low, this means the cpu is halted due to either the glue or cpu halting the computer due to a problem.

Test the address and data lines for activity, does one of them stay high or low but the rest show activity? If so then you may have a fault on that line. Try removing the cpu and power up the board, the address and data lines should all be 5V with the cpu removed.

Give that a go and we will go from there

[Oldskool]

Hi Dog,

Setting the tos jumper has some effect but no boot. (see fisrt post) The floppy does not try to boot. Floppy light does not come on. (gotek / kb)
Already tried different psu. No change.
Seems stuck in on the white screen.

PhilC,

Yes indeed I think so. The jumper on is tos 1.04.
So solder the socket on and try it with a normal 68000. And measure some stuff.
I think reset will work for sure.(without memory I see the reset work on screen) My feeling indeed is that the system is halted.

[exxos]

Did you see my previous post viewtopic.php?p=106493#p106493