An expensive A570 shaped paperweight ?

[dalek]

The volume knob disables the expansion so that behaviour is normal. Correct working process is A570 first, then A500.

To get the behaviour you are seeing, I'm guessing there might be either a power supply issue (or caps) or maybe the 7407 at U4E on the A570 which keeps the system reset line held low until the serial prom finishes loading the FPGA. Maybe check the cap at C12 on the A570 for the serial prom which may be weak.

[Vipersan]

Originally Posted by Sim085

Hi Vipersan, sorry to hijack your thread a little. I am planning to do same mod to my rev6a motherboard. How did you solder those header pins to the motherboard? I do not recall those are through-hole.

You need a steady hand ..
Cut the traces first and use treezers to hold the pin headers..
Put the link/jumper header pin blocks on 2 of the the pin headers first ..
This gives you something solid to grip with the tweezers and avoids burning your finger ends.
The bottom of the pin headers are pointed so get some snips and cut those points off in one go ...so all three points at once.
This gives a better flat base to offer up to the pcb.
Now apply flux to the solder points on the A500 pcb..
avoid sticky flux as this obscures the connections making it difficult to see what you are doing.
Tin the centre pin of the strip of 3 pins that was once pointed ..
apply a small ammount of solder to the centre pad only of the 3 on the A500 pcb ..
grip the pin header jumper combo with your tweezers and offer it up to the main pcb ....and tack the centre pin in place ..keeping the pin central and vertical ..
This is where you need a steady hand .
The outer 2 pins will now be slightly overhanging the pads on the A500 pcb ..but close enough to flow solder from pin to pcb..so do both outer pins.
When these have cooled ..return to centre pin that was tacked in place and apply a little more solder.
Job done ..clean and inspect the job with ISO ...remove the pin header jumper and check for any continuity between consecutive pins..
There should be none.


hope this helps.
use a jewellers eyeglass if like me your eyes are bad..it makes the job much easier.




@Dalek ...I will check the psu as you suggest by substituting another I have spare from the other A500.
At some point I'll open the A570 up again and check the components you suggest.


rgds 2 all and stay safe

[torsti76]

I'd generally recommend against soldering throughhole stuff to SMD pads. The pads are not up to the stress this exerts to them. The surface contact area of throughhole components is just too small in relation to their size and the leverage this induces.

If you really want jumper headers on SMD pads, take proper SMD pin strips. They have "feet" that are bent in alternating directions. Also, the plastic is usually much stiffer to prevent any unwanted movement.

[Vipersan]

Originally Posted by dalek

The volume knob disables the expansion so that behaviour is normal. Correct working process is A570 first, then A500.

To get the behaviour you are seeing, I'm guessing there might be either a power supply issue (or caps) or maybe the 7407 at U4E on the A570 which keeps the system reset line held low until the serial prom finishes loading the FPGA. Maybe check the cap at C12 on the A570 for the serial prom which may be weak.

Maybe differences between pcbs Dalek ..
Stripped down the A570 again ..and located a 7407 at U4 not U4E

desoldered it and fitted a turnpin socket ..which will make testing by substitution easier ..assuming it is the same device.
C12 is a small bue ceramic ...?
I assume you refer to this ?
it doesn't read short circuit ..and I have never known one to fail open..?
rgds
VS

[Vipersan]

Originally Posted by torsti76

I'd generally recommend against soldering throughhole stuff to SMD pads. The pads are not up to the stress this exerts to them. The surface contact area of throughhole components is just too small in relation to their size and the leverage this induces.

If you really want jumper headers on SMD pads, take proper SMD pin strips. They have "feet" that are bent in alternating directions. Also, the plastic is usually much stiffer to prevent any unwanted movement.

I cannot disagree with torsti on this ..
You use my method at your own risk ..but since there is no stress from wires attached...and simply jumpers which aren't moved often ..
I personally dont mind this risk.
rgds
VS

[Vipersan]

So ..changed the 7407 out ..and occasionally it will boot the A570 using the correct sequence of psu power up..
Approx 1 time in 5.
but changing the A570 psu as well ... has reduced this variance to 50 : 50
Time to look at recapping the A570 PSU as well I think.
I have to conclude this is a mostly psu issue really ..but a replacement 7407 has definately helped.
thanks for your insight Dalek.
rgds
VS

[Sim085]

Originally Posted by Vipersan

You need a steady hand ..

Originally Posted by torsti76

I'd generally recommend against soldering throughhole stuff to SMD pads.

Originally Posted by Vipersan

I cannot disagree with torsti on this ..

Thank you both for the advice. I will not hijack this thread any further but wanted to still share my gratitude for the very detailed answers given .

[dalek]

Originally Posted by Vipersan

Maybe differences between pcbs Dalek ..
Stripped down the A570 again ..and located a 7407 at U4 not U4E

desoldered it and fitted a turnpin socket ..which will make testing by substitution easier ..assuming it is the same device.
C12 is a small bue ceramic ...?
I assume you refer to this ?
it doesn't read short circuit ..and I have never known one to fail open..?
rgds
VS

Yep sounds like a difference to the schematics to the silkscreen (I don't have mine out/open at the moment to compare). Caps to check would be the ones closest to the 7407 and the serial prom.


Glad to hear it's on the improve

[Vipersan]

Ok ..recapped the A570 PSU ..and that 50:50 is now 100%
Next job ..find something to actually play on it ?
I've downloaded a few ..'titles'
and so far have had little success ..
Sim City ..appears to run ..and gets as far as starting a new game.
Spirit of Excalibur starts ..and brings up the Virgin logo ...then ..nothing.
Cover Girl strip poker ..wont start at all ..but then may have burned it wrong as it isn't in the bin cue format ..rather .img .cue ??
So
My next question to avoid burning multiple 'coasters'..
Is there a definitive list of which CDTV titles will run on the A570/A500 combo ?
rgds
VS

[torsti76]

Congratulations for getting it running.

As I've said earlier, I've had the combination in the past and was also a little disappointed about the lack of actual titles.
So, I ended up using the fancy audio CD player most of the time...

[Vipersan]

Originally Posted by torsti76

Congratulations for getting it running.

As I've said earlier, I've had the combination in the past and was also a little disappointed about the lack of actual titles.
So, I ended up using the fancy audio CD player most of the time...

Hi Torsti ..
I realised this might be disapointing when I started the 'quest' as it can never truely be a CDTV player..
..but I did expect at least a few titles to run ok.
I like the idea of the music player ...that's a plus ..
..but would like too have at least a handfull of playable games as well.
I could just spend hours burning and testing with CDRW..but it would narrow down the search ..if other users had already got a list of workable titles to choose from.
rgds
VS

[Vipersan]

Just found this recent youtube video on the A570.
Very useful info indeed...and have just ordered a scsi interface board for mine.
It wasn't cheap (gulp !) ...and now I also want the 2mb A570 internal ram card..but am having problems finding one for sale ?
anyone ?
[ Show youtube player ]
rgds
VS

[torsti76]

Here's a DIY variant: https://www.amigaworld.de/hardware/a572-ram-expansion/

It's been recently tested and reported to work well...

[Vipersan]

Thanks Torsti ..
whilst I would be happy to make one up ..
getting hold of the connector and pcb might be a issue..
Does anyone offer this in kit form ?
rgds
VS

[Vipersan]

Hmm ...
Just found this also ..during my online searching..
Designed by Dalek..
Too much of a coincidence I think..
Is this the Dalek I am in contact with through EAB ?
https://dirtypcbs.com/store/designer...0-cd-rom-drive
He has my email address so perhaps will contact me directly.
fingers crossed.
rgds
VS

[Vipersan]

Problem solved ..
I found an old ebay listing for a ready built unit ..
They were no longer listed ..and had exired.

..and contacted the seller and asked if he still had them..?
just got a reply.
Yes ...and he still had some so immediately listed 2 more.
I just snapped one up.
Just in case someone else requires one ..
This is the listing..
https://www.ebay.co.uk/itm/Amiga-A57...72.m2749.l2649

[torsti76]

Ah, I'd have recommended this thread in any other case over at forum64: https://www.forum64.de/index.php?thr...a570/&pageNo=5

They built several pieces of the Amigaworld version.

[Vipersan]

Thanks for your help Torsti.
Looking forward to having a bit more dedicated ram...and testing out the scsi interface when it comes.
rgds

[alexh]

Pick up some Amiga magazine coverdiscs on eBay. Most boot straight to workbench. It's amazing what you can do with one of these discs and no hard drive. I had an A570 + A500plus + 2MB expansion for about a year before getting a HDD

[dalek]

Originally Posted by Vipersan

Hmm ...
Just found this also ..during my online searching..
Designed by Dalek..
Too much of a coincidence I think..
Is this the Dalek I am in contact with through EAB ?
https://dirtypcbs.com/store/designer...0-cd-rom-drive
He has my email address so perhaps will contact me directly.
fingers crossed.
rgds
VS

Yeah that was me See here: https://github.com/daleking/Amiga_A570_2MB


It's amazing what comes out of the woodwork when you release something opensource


Glad to see you got one though. The connector is a standard part either from a reputable source or ebay. The DRAM chips can be had off old DIMMs or found on ebay quite easily.


I still have a few PCBs but only makes sense for me to send them within Australia - if you are overseas it would be easier just to order your own from a cheap pcb fab.