people with a A5000 iss1 and scope ?

[duikkie]

just asking

is there a schematic for A5000 iss 1 ? , i have the one with IOEB chip

are there any scoop pictures ?

i have a clk signal but amplitude 1 volt ?? on the vidc chip freq looks good 20 ns high, 20ns low but 1 volt ??

a little bit of help

[duikkie]

every thing is old

scoop delay 0.02 uS :1volts

[duikkie]

are the chips on the right place ?

[duikkie]

too difficult ? or are there no people with A5000 iss1 ?

[Multiwizard]

Hi,

don't worry your not the only one...

Sometimes it just happens, nobody replies...

Last year I posted this, I also had a overwhelming list of replies :

viewtopic.php?f=9&t=14466&p=193074#p193074


Greetings, Wim...

[danielj]

If no one replies it's usually because no one knows the answer

(and 20 people replying with "sorry, I don't know" would be a bit "me too!"

[duikkie]

I wonder are there no People wit A5000 or are there not People with a scoop ?

It is very difficult if there is no schematic of the iss1 and if the chips with label are wrong then you have real problem s

I know something About beeb this is my frist A5000 and because it was free from
an other dutch acorn user

[Elminster]

Well I am only reading the article because I wondered why you were using an A5000 as a shovel. I thought it meant scoop as in

'a tool with a deep bowl-shaped end that is used to dig out and move a soft substance or powder '

I do have a scoop but not an A5000

[duikkie]

Is scoop a dutch thing ?

[TimoHartong]

too difficult ? or are there no people with A5000 iss1 ?

Would it be possible to make a picture of the whole motherboard I can then have a look at the A5000's I have if I have a Issue 1 board. And I would say scoop is a Dutch spelled.
Yes, I have a cathoderay oscilloscope ( actually 3 )

[duikkie]

The iss 1 board is with the chips see picture

The other board is with a big chip

Is scope a beter word ?

too difficult ? or are there no people with A5000 iss1 ?

Would it be possible to make a picture of the whole motherboard I can then have a look at the A5000's I have if I have a Issue 1 board. And I would say scoop is a Dutch spelled.
Yes, I have a cathoderay oscilloscope ( actually 3 )

[duikkie]

O no not a #acornmetoo

If no one replies it's usually because no one knows the answer

(and 20 people replying with "sorry, I don't know" would be a bit "me too!"

[danielj]

Argh, that's not actually what I meant! I just meant when someone posts "I don't like whatever" and a million people post "yeah, me too."

[steve3000]

It is very difficult if there is no schematic of the iss1 and if the chips with label are wrong then you have real problem s

There is a schematic for this PCB. There are two versions of the A5000 TRM, the first version contains the circuit diagram for the early machine, that you have. Both TRMs are available online, although not clearly labelled as to which diagram they contain.

I think I posted up some links to these a few years ago?

Unfortunately on holiday right now with only my phone and nearly no data signal, so I can't easily locate these.

[Multiwizard]

If no one replies it's usually because no one knows the answer

(and 20 people replying with "sorry, I don't know" would be a bit "me too!"

Hi Daniel,

of course I totally knew I was asking for hens teeth...


Greetings, Wim...

[Elminster]

Is scoop a dutch thing ?

Well I never heard of it being referred to as a scoop before. So I guess so. That or I have lived a sheltered life. As you say in a later post, scope would be more usual. But now I know!

And you have loads of responses now. Just most not relevant to your issue

[duikkie]

Take your time it is a project a have allo holiday

It is very difficult if there is no schematic of the iss1 and if the chips with label are wrong then you have real problem s

There is a schematic for this PCB. There are two versions of the A5000 TRM, the first version contains the circuit diagram for the early machine, that you have. Both TRMs are available online, although not clearly labelled as to which diagram they contain.

I think I posted up some links to these a few years ago?

Unfortunately on holiday right now with only my phone and nearly no data signal, so I can't easily locate these.

[steve3000]

Turned out to be easier than I thought to locate. TRM and PCB diagrams linked from my previous postings below. The A5000 PCB diagrams are from Chris' Acorns, and include the pre-IOEB circuits on page 4 of the diagrams "Acorn_A5000TRM_MainPCBCircuitDiagram4of4.pdf"

New scans of A5000 TRM (warning 61mb file!): here
A5000 PCB drawings (.zip from Chris's Acorns at computing history): here

[duikkie]

Thanks I Will look after my holiday

Turned out to be easier than I thought to locate. TRM and PCB diagrams linked from my previous postings below. The A5000 PCB diagrams are from Chris' Acorns, and include the pre-IOEB circuits on page 4 of the diagrams "Acorn_A5000TRM_MainPCBCircuitDiagram4of4.pdf"

New scans of A5000 TRM (warning 61mb file!): here
A5000 PCB drawings (.zip from Chris's Acorns at computing history): here

[TimoHartong]

are the chips on the right place ?

Hi duikkie,

During my cold / flew when I was I out bed I was able to open some A5000 computers and I have one with an issue 1 motherboard:




And by the looks of it all the PAL's on your photo are on the correct place. Please note this board has an issue but that is because of battery leakage ;-(

[duikkie]

Thanks my board is dead over a few day a gone look at the signals from kristal to video chip .

Maybe I see a low or bad signal?

[TimoHartong]

Hi,

Do you remember on which pin you measured the clk to the VIDC ( LK6 ) ?

[duikkie]

Pin 1-2 of lk6

Hi,

Do you remember on which pin you measured the clk to the VIDC ( LK6 ) ?

[TimoHartong]

OK,

Here some pictures:

The HAMEG used to do the measurements. I didn't feel in that good health to get the tektronix from the shed.

Picture of the probe near the VIDC link. I got the ground from a link nearby. Yes I know that at these frequency the shorter the better, but this was an indicative measurement

The prope is at 10:1 so the voltage is nicely 5 Volts top top.

24 MHz

And the screen.As I said this board has other problems
P.S. I do like the scopes with a real CRT.

[TimoHartong]

Is scoop a dutch thing ?

Well I never heard of it being referred to as a scoop before. So I guess so. That or I have lived a sheltered life. As you say in a later post, scope would be more usual. But now I know!

And you have loads of responses now. Just most not relevant to your issue

Hopefully @duikkie has no more relevant posts

[duikkie]

jealous !!!

i have allso now about 5 volt on the video chip and about 24 mhz signal , ( i have to calculate )
and a lot of ghost signals but yeah it is old stuff

the big problem is that i do not have HS and VS so no picture

i have to study the video chip , what is output and what you really need
to get HS and VS out of the chip. that is in an other item

the hs is now contineu 5 volt and VS allways zero ( or the other way around)

the mean think is where to start looking i have CLK and ic10 gives on y pin a 24mhz signal

but i have to understand the video chip , i think it working on its own and if good then a HS and VS must be here all the time. no datalines is needed ?

OK,

Here some pictures:

The HAMEG used to do the measurements. I didn't feel in that good health to get the tektronix from the shed.

Picture of the probe near the VIDC link. I got the ground from a link nearby. Yes I know that at these frequency the shorter the better, but this was an indicative measurement

The prope is at 10:1 so the voltage is nicely 5 Volts top top.

24 MHz

And the screen.As I said this board has other problems
P.S. I do like the scopes with a real CRT.

[steve3000]

the big problem is that i do not have HS and VS so no picture

The VIDC must be programmed by the ARM before HS/VS will appear.

I suggest your issue is before the VIDC and more likely the ARM is not reading ROM correctly, so setup of VIDC, MEMC, IOC are not occurring.

[TimoHartong]

In the TRM there is a flow chart for a dead machines. Perhaps follow that ? Especially if you have a machine which doesn't even give a blinked LED at the floppy. But if you live in the Netherlands which I understand hopefully we have an evening in Delft ( Zuid Holland ) but I'm not sure if I'm there because I still a bit ill.

[duikkie]

are you sure ?
look at item more information about VIDC chip in A5000

in datasheet page 2
timing control = ckin pin 19 input
horizontal timing gives -hsyc, -hi
vertical timing give flbk and -v/cs

ckin= pin19 input 24mhz signal amplitude 5 volt ?
sink= pin20 input ......gnd=low
REFV=Rvdac pin43 input resistor from VDD
VSSV pin 42 gnd
VDDD pin 38 5 volt

i think this is the only signal the chip needs to give a -hsync signal

there is one thing : vertical sync width register must be 1 or more ?

the big problem is that i do not have HS and VS so no picture

The VIDC must be programmed by the ARM before HS/VS will appear.

I suggest your issue is before the VIDC and more likely the ARM is not reading ROM correctly, so setup of VIDC, MEMC, IOC are not occurring.