A500 trapdoor memory: free design - Page 19

katarakt · 28 April 2018, 13:41

Quote:

Originally Posted by PeteAU

I populated the real time clock and with a bit of minimal testing, it appears to work

The clock is completely optional of course, you don't need to bother with it if you don't want one.

The parts list for RTC:
U5 or U6: RTC62421/RTC72421/RTC62423/RTC72423
C10 or R7: 47K-100K 0805 resistor (yes a resistor!)
C12: 100nF 0805 capacitor
C13 or C19: >=2.2μF >=10V 0805 or 1206 tantalum
R1, R2, R3: 10K 0805 resistor
R4, R5: 220-470 0805 resistor
D1: BAT721C or BAT54C diode
Battery Holder: Some cheap ebay one.

I see you have used a quartz at Y1 and somewhere here i've read that this is not necessary, so i haven't paid much attention to it...is it better to use a quartz anyway if using RTC 62421A ? All ramexpansions i see are using a quartz

PeteAU · 30 April 2018, 10:53

Quote:

Originally Posted by katarakt

I see you have used a quartz at Y1 and somewhere here i've read that this is not necessary, so i haven't paid much attention to it...is it better to use a quartz anyway if using RTC 62421A ? All ramexpansions i see are using a quartz

Nope! RTC 62421A has a quartz crystal built-in.

8 Bit Dreams · 01 May 2018, 22:14

have built 68030 TK accelerator designed by Matze, also done Pete's Trapdoor expansion with GARY adapter.
Was very exited to test it, and here we are:

As You can see - memory is recognised correctly, works very nice! Really like it! Good job, PeteAU!! This setup allows to run a LOT of games!

Mathesar · 04 May 2018, 13:41

Nice machine you have there!

sampedenawa · 04 May 2018, 15:57

Quote:

Originally Posted by 8 Bit Dreams

have built 68030 TK accelerator designed by Matze, also done Pete's Trapdoor expansion with GARY adapter.

Where did you buy the 68030 and the FPU ?
Ain't easy to get ones for me

demolition · 04 May 2018, 16:18

Quote:

Originally Posted by sampedenawa

Where did you buy the 68030 and the FPU ?
Ain't easy to get ones for me

You could buy one of these and pull the CPU from it:

https://icomp.de/shop-icomp/en/shop/...t/ACA12xx.html

alenppc · 04 May 2018, 16:24

You can buy them easily on ebay.

sampedenawa · 04 May 2018, 16:45

Quote:

Originally Posted by alenppc

You can buy them easily on ebay.

Humm, not so easily for me:

https://www.ebay.it/sch/i.html?_odkw...030RC&_sacat=0

Lots of craps, fakes, untested .... can't afford 30-40€ each try ....

Any known reliable source ?

Quote:

Originally Posted by demolition

You could buy one of these and pull the CPU from it:
https://icomp.de/shop-icomp/en/shop/...t/ACA12xx.html

Could be a cheaper solution, indeed.

8 Bit Dreams · 05 May 2018, 20:58

Quote:

Originally Posted by Mathesar

Nice machine you have there!

Thanks Mathesar!
It is possible because of Your GARY adapter and PeteAU's board.. Really great job

!
I am very pleased how this setup works. Thank You very much guy's!

Quote:

Originally Posted by sampedenawa

Where did you buy the 68030 and the FPU ?
Ain't easy to get ones for me

Yes, indeed, prices are risen since TF530 was released, but this setup allows me to play WHDLoad and i can forget about floppy's, so i am ready to pay 35€ for CPU...

14 May 2018, 14:33

Hello,

I have equipped my first memory board with a memory chip IS41C16100S-50K.
Unfortunately, I always get a green screen on all mainboard variants.
The memory chip will probably not be the right type.
I thought 1M x 16 (16MBIT) DYNAMIC RAM WITH EDO PAGE MODE is OK.

Here is the datasheet:
http://www.alldatasheet.com/datashee...6100S-50K.html

Mq · 14 May 2018, 14:39

Check pins 4,6,10,17, they looks like not soldered properly, but it's not good visible on the picture. Green screen apears when there is bad soldering on one or more lines or when there are short circuits between two or more lines. Use magnifying glass, and take a look on every pins soldering carefuly.

14 May 2018, 14:54

Can I measure short circuits between the PINs with a multimeter?

Mq · 14 May 2018, 15:30

Yes, short circuits between the pins can be checked with a multimeter. But there are often bad soldering too, so use magnifying glass. Sometimes everything looks good, but soldering is not good.

About the pins numbers I previously recommend You to check: on the previous picture it looks like no soldering was on them, but on the second picture I see it was light reflexes.

14 May 2018, 20:34

Pin 22 and 23 had a short circuit (GND and A4)
Now it works as slowram.

@ Mq, thank you for the hint.
Visually, the solder joints looked good to me.
But the measurement with the multimeter showed the short circuit.

NC on pin 11 and 12 had me confused, but the data sheet brought the resolution.

Mq · 14 May 2018, 22:25

No problem:-) I'm glad I could help You:-)
I built seven such extensions for myself and my friends, and one board with sockets for memory chips testing:-)
At the beginning I did many mistakes, but last three or four extensions I could soldering with closed eyes:-)

watman · 15 May 2018, 22:42

AS an owner of Mq-made board I can tell that it's perfect, so he knows what he's talking about

katarakt · 17 May 2018, 21:03

edit: ups, i've posted in wrong thread

fpmpaolo · 31 May 2018, 11:37

Is there any chance to see something similar for A600?

8 Bit Dreams · 31 May 2018, 12:10

Quote:

Originally Posted by fpmpaolo

Is there any chance to see something similar for A600?

Yes
http://www.galerieallegro.pl/zdjecia...0390770/4#zdj6
but it will be discussed in other thread, if author decides to do it, not here

31 May 2018, 19:13

I just wanted to thank Pete for doing this board and everyone else who's helped evolve it, commented and tested it. I had ordered the PCBs and although still waiting on parts for the more complex gary adapter version I also built a couple of the simple 512k boards for my A500s that had damaged 501s. I think they cost me at most 3 dollars each to make.. Amazingly satisfying to watch a demo that needs 1meg on a board you put together for 3 dollars. I Really really appreciate it. It also got me wondering if this can be adapted to the side port of the A1000 but maybe that's for another time

.

01 May 2018, 22:14	#363
8 Bit Dreams Retro maniac Join Date: Feb 2017 Location: near Munich / Germany Posts: 486	have built 68030 TK accelerator designed by Matze, also done Pete's Trapdoor expansion with GARY adapter. Was very exited to test it, and here we are: As You can see - memory is recognised correctly, works very nice! Really like it! Good job, PeteAU!! This setup allows to run a LOT of games! Last edited by 8 Bit Dreams; 01 May 2018 at 22:40.

14 May 2018, 14:33	#370
MalleB Posts: n/a	Hello, I have equipped my first memory board with a memory chip IS41C16100S-50K. Unfortunately, I always get a green screen on all mainboard variants. The memory chip will probably not be the right type. I thought 1M x 16 (16MBIT) DYNAMIC RAM WITH EDO PAGE MODE is OK. Here is the datasheet: http://www.alldatasheet.com/datashee...6100S-50K.html Last edited by MalleB; 14 May 2018 at 14:47.

14 May 2018, 15:30	#373
Mq Registered User Join Date: Aug 2017 Location: Poznan/Poland Posts: 73	Yes, short circuits between the pins can be checked with a multimeter. But there are often bad soldering too, so use magnifying glass. Sometimes everything looks good, but soldering is not good. About the pins numbers I previously recommend You to check: on the previous picture it looks like no soldering was on them, but on the second picture I see it was light reflexes. Last edited by Mq; 14 May 2018 at 15:35.

17 May 2018, 21:03	#377
katarakt Registered User Join Date: Jul 2017 Location: Germany Posts: 205	edit: ups, i've posted in wrong thread Last edited by katarakt; 27 May 2018 at 15:20.

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04 May 2018, 13:41	#364
Mathesar Registered User Join Date: Aug 2014 Location: Netherlands Posts: 699	Nice machine you have there!

04 May 2018, 16:24	#367
alenppc Registered User Join Date: Apr 2012 Location: Canada Age: 44 Posts: 910	You can buy them easily on ebay.

14 May 2018, 14:39	#371
Mq Registered User Join Date: Aug 2017 Location: Poznan/Poland Posts: 73	Check pins 4,6,10,17, they looks like not soldered properly, but it's not good visible on the picture. Green screen apears when there is bad soldering on one or more lines or when there are short circuits between two or more lines. Use magnifying glass, and take a look on every pins soldering carefuly.

14 May 2018, 14:54	#372
MalleB Posts: n/a	Can I measure short circuits between the PINs with a multimeter?

14 May 2018, 20:34	#374
MalleB Posts: n/a	Pin 22 and 23 had a short circuit (GND and A4) Now it works as slowram. @ Mq, thank you for the hint. Visually, the solder joints looked good to me. But the measurement with the multimeter showed the short circuit. NC on pin 11 and 12 had me confused, but the data sheet brought the resolution.

14 May 2018, 22:25	#375
Mq Registered User Join Date: Aug 2017 Location: Poznan/Poland Posts: 73	No problem:-) I'm glad I could help You:-) I built seven such extensions for myself and my friends, and one board with sockets for memory chips testing:-) At the beginning I did many mistakes, but last three or four extensions I could soldering with closed eyes:-)

15 May 2018, 22:42	#376
watman Registered User Join Date: Apr 2018 Location: Poland Posts: 36	AS an owner of Mq-made board I can tell that it's perfect, so he knows what he's talking about

31 May 2018, 11:37	#378
fpmpaolo Registered User Join Date: Aug 2014 Location: Bologna / italy Age: 43 Posts: 135	Is there any chance to see something similar for A600?

31 May 2018, 19:13	#380
the_master Posts: n/a	I just wanted to thank Pete for doing this board and everyone else who's helped evolve it, commented and tested it. I had ordered the PCBs and although still waiting on parts for the more complex gary adapter version I also built a couple of the simple 512k boards for my A500s that had damaged 501s. I think they cost me at most 3 dollars each to make.. Amazingly satisfying to watch a demo that needs 1meg on a board you put together for 3 dollars. I Really really appreciate it. It also got me wondering if this can be adapted to the side port of the A1000 but maybe that's for another time .

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