Opinion on a damaged E703 on an A500Plus mobo

[Xanxi]

Hi.

My A500 Plus mobo seems to have a broken component near the side expansion slot, which i think came from too much stacking of cards when i tried to assemble those CPU relocator, clockport expansion and various vicious accelerators that didn't want to work.

Is it really broken?
Should it be replaced?
What issue could it cause?

Thanks for your opinion.

 

[roy_bates]

i think this connects the -12 volt to pin 8 of the expansion port on the outer pins,the center pin is a 0.01uf capacitor 10nf? connected to the middle of it

if it isnt shorted to the middle pin either end,i would leave it be

unless someone else steps in and suggests otherwise

 

[Buzzfuzz]

These are filters as far as I know, they either work or they don't, so if your board is working, wouldn't worry about it

 

[Xanxi]

The computer is working good but i am not sure about the expansion port.
I have only used it a few days ago for testing AmigSID boards with a zorro converter. With a real SID it worked but some songs had very faint audio level with no reason. With another type of chip, i got a lot of noise. I don’t know if that board is using -12V or not.
I have to test with an A570 which have been in storage a long time but need to find a caddy first.

 

[roy_bates]

well,a sid doesnt use -12 for anything,unless the board uses op amps

do you have a link, i havnt heard of this device

as for the a570 i dont think its uses the minus 12 for anything

 

[Xanxi]

That's the board from here https://www.pcbway.com/project/shareproject/AmigaSID_Zorro_II_card_rev2_30dddeb1.html

 

[roy_bates]

nope doesnt use the minus 12 for anything i looked at the schematics

im curious though as the board can take two different types of sid,i can tell you they use different filters and different voltages

i know this isnt what the thread is about,but it was worth a mention,i dont know what sid your using and the schematics show filters for a later sid even though the voltage is selectable between 12 and 9,a 6581 uses 470pf filters the later one is 2200pf
and i cant see a way to select a filter type(schematic for this device shows 2200pf filters)

 

[roy_bates]

yeah,i had a look at the pictures the filters are on the back side of the board,and not selectable,i would call that design oversight
so,once the filters are soldered on the board you are stuck with one type of sid,having the voltage selectable is odd without sid filter select

 

[Xanxi]

Thanks for spending time on this.
Yes the board can be jumpered to 9V or 12V as required for the MOS 8560 or MOS 6581 respectivly. For the other SID recreations, it depends. The SIDKick-pico for instance don't care about the voltage as it uses only 5V from another pin. The only other option is to select the memory adress by a set of jumpers.
Anyway, that is possible that this Zorro board requires a better CPU than the 14 MHz 68010 of my A500Plus, so i can't troubleshoot my E703 for sure with this.
I will try next the A570 and report.

 

[Xanxi]

Hi.
So i have tested the A570 on my side slot.
The A570 itself has been in storage 15 to 20 years without possibilty to use it because it was not compatible with the board installed in that computer at that time.
So i can't be sure it is actually working at all.
Anyway, i have connected it, powered first the A570 then the A500Plus. The drive makes a mechanical sound and its led is lit.
Unfortunately, that red screen is the best i can get, sometimes only black screen.
Those Manufacturer and Product numbers are the one attached to the Spitfire 500 which is recognized as an Octagon 2008 and RAM expansion in Sysinfo.
So, i still can't tell if there is an issue with
- the A570 not working
- the Spitfire conflicting with the A570, either the board, the RAM or the clock at 14 MHz.
- a problem related to the damaged component
- maybe the ROM which is 2.05 from A600 as my old 2.04 is not working. The A570 was made obviously for the A500 under 1.3 or the A500Plus with 2.04

 

[roy_bates]

why not revert the machine back to near original spec and see what works

 

[Xanxi]

Yes i need to do that but inserting and desinserting those CPU expansions in the 68000 socket is always perilous. Will try next week, i must change the partitions on the CF to accomodate the KCS PowerPC and the A-Max at the same time.

 

[Xanxi]

I have noticed on the spitfire gifthub something about the A590 that could apply to the A570.

SF500 and A590​

With the updated firmware it's now possible to use an A590 (on the A500 expansion edge) togheter with a SF500.
You will need to solder/connect a jumper-wire from the CFGOUT-goldfinger-pad and run it to the CFGIN-pin on the SF500. This will asure that there will be no conflict during AutoConfig cycles. They will be daisy-chained meaning the A590 configures first and the SF500 is second in line.



What is called the goldfinger pad seems to be the edge connector of the Amiga. I'm not sure i would like to solder directly on my mobo though.

 

[Xanxi]

Here is the situation.
I have soldered that wire to the 6th golden pad from the top as per picture and this mod does allow the A570 to work and i can boot to the WB from my CF, only if the A570 know is completly turned left (off). Then is it dectected in Sysinfo as A2091/A590 device.
If it is turned right, only black screen : supposedly, new CDTV ROM 2.35 could solve this issue.
However, with the wire pluged on CFGIN and without the A570, the A500Plus only boots to 2.0 kickstart screen and does not autoconfig the Spitfire stuff. That's annoying because the A570 can't be just used as plug and play unless the case stays open to put on or off the wire.

I have also briefly tested the A570 with a TF536 and no CF. It boots even from CDTV side but the boot screen is red tinted, with wrong colors, don't know why so far.

So the A570 seems at least partially working. I need to test some CD but surely cf filesystem have to be installed first.

Even if this is not directly related anymore to my original issue, i give full details because someone could stumbled on this thread in 20 years when facing the same issue (myself included as i could forgot what i did).