A520 Circuit

craggus2000 · 20 October 2010, 21:50

Me again...
I don't suppose anyone has a parts list and pcb design for an A520 on the off chance they've made their own? I'm looking to transfer an existing A520 to a new PCB which I plan to etch myself, except to turn it more in to a lead - with a few other mods - than a box on the back of my miggy. Currently trying to make my own based on the current pcb and keep going

trying to follow it all and find what all the components are!
Thanks muchly

pandy71 · 20 October 2010, 22:19

https://encrypted.google.com/url?sa=...QltvyM_soODxlw

MC1377 is quite poor quality color coder and modulator... use Analog Devices or Philips (NXP) coders.

craggus2000 · 20 October 2010, 22:33

Quote:

Originally Posted by pandy71

https://encrypted.google.com/url?sa=...QltvyM_soODxlw

MC1377 is quite poor quality color coder and modulator... use Analog Devices or Philips (NXP) coders.

Thanks, that's a good start!
Do you know what type of device FB1 is? and the L devices?
Can I just swap out the MC1377 for an AD724 (obviously taking into account possible change in pin posisitons? or is anything else required?

pandy71 · 20 October 2010, 22:47

FB Ferrite Bead - ferrite tube with wire inside, L are inductance (coil) - (both FB and L are inductances)

Better is recreate circuit form A600/A1200/CD32 than recreate A520)

And MC1377 and AD724 are not compatible - they are not swappable

craggus2000 · 20 October 2010, 23:16

Quote:

Originally Posted by pandy71

FB Ferrite Bead - ferrite tube with wire inside, L are inductance (coil) - (both FB and L are inductances)

Thanks

Quote:

Originally Posted by pandy71

Better is recreate circuit form A600/A1200/CD32 than recreate A520)

How is it better than the A520?

Don't suppose you know what the circuit is?

pandy71 · 20 October 2010, 23:46

Sony CXA1145M

craggus2000 · 20 October 2010, 23:48

Quote:

Originally Posted by pandy71

Sony CXA1145M

??

pandy71 · 20 October 2010, 23:57

circuit for color encoder from AA600/1200/CD32 is CXA1145M (made by SONY) - better than in A520 - MC1377 is from second half of 70's last century - seems to be almost 40 years old

rkauer · 21 October 2010, 02:57

The successor of the CXA1145 (CXA1645) is still in production and have a better design, use the proposed circuit on its datasheet to create your own encoder.

craggus2000 · 22 October 2010, 11:02

Quote:

Originally Posted by pandy71

https://encrypted.google.com/url?sa=...QltvyM_soODxlw

MC1377 is quite poor quality color coder and modulator... use Analog Devices or Philips (NXP) coders.

Anyone know where there might be a slightly more legible version of this circuit diagram? Can't tell all the values!

Thanks

Zetr0 · 22 October 2010, 13:05

@craggus2000

Are you trying to build an SVideo Y/C and or composite output ?

pandy71 · 22 October 2010, 14:29

https://encrypted.google.com/url?sa=...4gE6iZlD4vqfAg

i not expect any better A520 schematics - this german one is very good and almost all values can be readied directly or deducted especially with help of the MC1377 datasheet.

Zetr0 · 22 October 2010, 16:33

@Craggus

to be honest it would be far easier, quicker and cheaper to make an external SVideo Y/C device -

with a little bit of hackery and jump wire you can do this with a $5 AD724 Svideo encoder =)

you can even hack whats left of the A520 you have to provide

1. 23pin video connector
2. a 4.43 PAL colour encoding crystal
3. A composite output
4. A nice housing for your project

Have a look here

craggus2000 · 24 October 2010, 23:17

Quote:

Originally Posted by Zetr0

@Craggus

to be honest it would be far easier, quicker and cheaper to make an external SVideo Y/C device -

with a little bit of hackery and jump wire you can do this with a $5 AD724 Svideo encoder =)

you can even hack whats left of the A520 you have to provide

1. 23pin video connector
2. a 4.43 PAL colour encoding crystal
3. A composite output
4. A nice housing for your project

Have a look here

Thanks Zetr0,
Well, what I actually want to do (just for the fun of it..............

), is to compare for my own satisfaction, an unmodded a520, an a520 with svideo mod, a completely 'new' (rebuilt from brand new (original) components and newly etched) a520 with svideo mod, and something like the 'narmi external' adapter (or amigamaniac's version but would prefer to make it myself) to see what the differences are.
Incidentally do you know if the circuit here (Narmi's) is complete and fully functional? I need it to be pal, so would the attached change to it be all I need to do to output composite and pal?

craggus2000 · 24 October 2010, 23:29

Quote:

Originally Posted by Zetr0

you can even hack whats left of the A520 you have to provide

1. 23pin video connector

Does anyone know where I can get these new? can't seem to find any in the UK, only male versions... Anyone have any spares they could part with? or know where I can get them?

pandy71 · 25 October 2010, 01:22

So this circuit has one problem - PAL chroma burst is different than C1 available on Video connector (pin 15) - to have proper PAL chroma burst signal fully synchronized to Amiga system you need to multiply C1 by 10 (PLL? NE564?) then divide it by 8 to receive 4433618,75Hz from 3546895Hz

Loedown · 25 October 2010, 04:16

Quote:

Originally Posted by craggus2000

Does anyone know where I can get these new? can't seem to find any in the UK, only male versions... Anyone have any spares they could part with? or know where I can get them?

Made by Foxconn, WES Components in Sydney Australia stock them.

craggus2000 · 10 November 2010, 10:03

Decided to give up on this and am buying one from AmigaManiac!

20 October 2010, 21:50	#1
craggus2000 Registered User Join Date: Oct 2010 Location: Braintree, Essex, UK Age: 39 Posts: 126	A520 Circuit Me again... I don't suppose anyone has a parts list and pcb design for an A520 on the off chance they've made their own? I'm looking to transfer an existing A520 to a new PCB which I plan to etch myself, except to turn it more in to a lead - with a few other mods - than a box on the back of my miggy. Currently trying to make my own based on the current pcb and keep going trying to follow it all and find what all the components are! Thanks muchly

20 October 2010, 22:19	#2
pandy71 Registered User Join Date: Jun 2010 Location: PL? Posts: 2,748	https://encrypted.google.com/url?sa=...QltvyM_soODxlw MC1377 is quite poor quality color coder and modulator... use Analog Devices or Philips (NXP) coders. Last edited by pandy71; 20 October 2010 at 22:27.

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20 October 2010, 22:47	#4
pandy71 Registered User Join Date: Jun 2010 Location: PL? Posts: 2,748	FB Ferrite Bead - ferrite tube with wire inside, L are inductance (coil) - (both FB and L are inductances) Better is recreate circuit form A600/A1200/CD32 than recreate A520) And MC1377 and AD724 are not compatible - they are not swappable

20 October 2010, 23:46	#6
pandy71 Registered User Join Date: Jun 2010 Location: PL? Posts: 2,748	Sony CXA1145M

20 October 2010, 23:57	#8
pandy71 Registered User Join Date: Jun 2010 Location: PL? Posts: 2,748	circuit for color encoder from AA600/1200/CD32 is CXA1145M (made by SONY) - better than in A520 - MC1377 is from second half of 70's last century - seems to be almost 40 years old

21 October 2010, 02:57	#9
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	The successor of the CXA1145 (CXA1645) is still in production and have a better design, use the proposed circuit on its datasheet to create your own encoder.

22 October 2010, 13:05	#11
Zetr0 Ya' like it Retr0? Join Date: Jul 2005 Location: United Kingdom Age: 49 Posts: 9,768	@craggus2000 Are you trying to build an SVideo Y/C and or composite output ?

22 October 2010, 14:29	#12
pandy71 Registered User Join Date: Jun 2010 Location: PL? Posts: 2,748	https://encrypted.google.com/url?sa=...4gE6iZlD4vqfAg i not expect any better A520 schematics - this german one is very good and almost all values can be readied directly or deducted especially with help of the MC1377 datasheet.

22 October 2010, 16:33	#13
Zetr0 Ya' like it Retr0? Join Date: Jul 2005 Location: United Kingdom Age: 49 Posts: 9,768	@Craggus to be honest it would be far easier, quicker and cheaper to make an external SVideo Y/C device - with a little bit of hackery and jump wire you can do this with a $5 AD724 Svideo encoder =) you can even hack whats left of the A520 you have to provide 1. 23pin video connector 2. a 4.43 PAL colour encoding crystal 3. A composite output 4. A nice housing for your project Have a look here

25 October 2010, 01:22	#16
pandy71 Registered User Join Date: Jun 2010 Location: PL? Posts: 2,748	So this circuit has one problem - PAL chroma burst is different than C1 available on Video connector (pin 15) - to have proper PAL chroma burst signal fully synchronized to Amiga system you need to multiply C1 by 10 (PLL? NE564?) then divide it by 8 to receive 4433618,75Hz from 3546895Hz

10 November 2010, 10:03	#18
craggus2000 Registered User Join Date: Oct 2010 Location: Braintree, Essex, UK Age: 39 Posts: 126	Decided to give up on this and am buying one from AmigaManiac!

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