Dead EZ-VGA Scandoubler (external)

manicx · 26 March 2011, 18:15

Hello everyone

My old friend, an extrernal EZ-VGA Scandoubler died today. A HDD failure (a crappy Hitachi 2.5" that almost got fire) made me try to unplug the mains from Amiga and the scandoubler was removed slightly and I heard a 'chuf'. I am not sure if I can fix this (I think a capacitor died). What alternatives do I have? Are there any external scandoublers sold these days?

Crap day!

rkauer · 26 March 2011, 20:57

It's worth a check inside the Amiga: when something plugged in the video port is sacked on live, the most common behaviour is a SMD resistor bit back of the video port get burned.

Check the resistors prior to think your scandoubler is dead.

manicx · 26 March 2011, 23:43

Actually, I hooked the Amiga with a scart cable on a TV and it is working. I opened the scandoubler and one of the capacitors looks a bit lifted from the pcb.

rkauer · 27 March 2011, 04:01

Does the SCART cable using both the +12 & +5V from the video port?

Changes are that one of the power lines get its protection SMD resistor cracked.

manicx · 27 March 2011, 18:58

Quote:

Originally Posted by rkauer

Does the SCART cable using both the +12 & +5V from the video port?

Changes are that one of the power lines get its protection SMD resistor cracked.

No idea. It is an ordinary Amiga RGB-> Scart Cable. Problem with scandoubler is that after I heard that horrible sound, it smelled like burned and not the Amiga.

manicx · 27 April 2011, 16:22

After a thorough look inside the scadoubler and with the help of AmigaKit tech department, I found that the Mach chip had a hole on it.

Good thing is that I found a Mach chip replacement sold in AmigaKit. I replaced the old one and even though the SD is not dead now and it starts, the picture I get is blurry to the extend that it is unusable.

The thing is that I don't know if the Mach chip I bought is pre-programmed. And second thing is that if it is, why is the image so blurry? I tried adjusting the little screw on the back of the SD but had no luck.

If the Mach chip is not programmed, does anyone program such PLCC Mach chips? Really need help with this...

rkauer · 27 April 2011, 22:14

The MACH chip is programmed (think of it like a big PIC chip).

The blurry image may be from other problem (a bad capacitor or dodgy soldering somewhere).

FOL · 28 April 2011, 00:16

Quote:

Originally Posted by rkauer

The MACH chip is programmed (think of it like a big PIC chip).

The blurry image may be from other problem (a bad capacitor or dodgy soldering somewhere).

As it blew a hole in the chip, I would think its a problem related.
Another component damaged.

@manicx
Check for other damaged components, as I only spotted the mach chip by chance while scanning your pics.

manicx · 28 April 2011, 11:54

Thanks for your answers...

I uploaded some images. I am trying to figure out some things but frankly, my knowledge on electronics is limited. My only suspicion may be on the SMD 22uF 16V capacitor above the Mach chip. It looks a bit lifted compared to the other ones.

Some pics:

http://i28.photobucket.com/albums/c2...s/DSCN1631.jpg

http://i28.photobucket.com/albums/c2...s/DSCN1637.jpg

http://i28.photobucket.com/albums/c2...s/DSCN1638.jpg

I am not sure what to look on capacitors or other components. Any help with this is appreciated. I cannot see a similar 'hole' on any other chip and I am stuck a bit with this...

rkauer · 29 April 2011, 04:02

I didn't see anything wrong from the pictures. Please pry out and reinsert the little AV9170 (A/D converter) into its socket and try again.

Other than that, replacing the old capacitors is always a wise choice.

Hewitson · 29 April 2011, 08:58

The pin which is on the top left of the Mach in the first pic looks like it's bent.

8bitbubsy · 29 April 2011, 09:49

Quote:

Originally Posted by Hewitson

The pin which is on the top left of the Mach in the first pic looks like it's bent.

Looks like a snug fit if you ask me

Just a bit bent out, but should be no problem... It's not strong enough to push the other pins away from the connector. It looks like the other pins have no contact, but the connector pins are bulging out in the middle so no worries.

Hewitson · 29 April 2011, 10:19

Yeah I agree, I wasn't suggesting it was the problem. Still worth taking a quick look at though IMO

manicx · 29 April 2011, 11:15

Thanks everyone.

Aparently, these are pics before I replace the Mach. Sorry!

I will make a new pic after the replacement. Basically, PLCC usually make contact around halfway to the socket, at least from what I have seen. But I suppose, I can try and lift each pin a bit with maximum caution and lots of patience. Right?

I will also try and reinsert the AV9170. If the problem persists, I will try and see where I can replace the SMD capacitors since I can't do such thing myself.

Loedown · 29 April 2011, 12:09

Blurry picture suggests one of the components has failed as opposed to a chip failure.

Raised capacitors aren't an issue, when they are placed onto the boards it is possible that the leg(s) were slightly bent and as long as some part of both legs in within the bounds of the solder it will be fine.

I have a limited understanding of scandoublers, but I have seen VGA monitors lose their focus ( if it's an old CRT type ). To me it sounds like a biasing issue on one of the chips, much the same as A4000 audio issues when a voltage rail is missing, the horrible distortion you get when the -12V signal isn't present for example.

manicx · 02 May 2011, 11:51

Some more pics with the new Mach. As you can see, it is a tight fit...

http://i28.photobucket.com/albums/c2...s/DSCN1668.jpg
http://i28.photobucket.com/albums/c2...s/DSCN1670.jpg
http://i28.photobucket.com/albums/c2...s/DSCN1672.jpg
http://i28.photobucket.com/albums/c2...s/DSCN1673.jpg
http://i28.photobucket.com/albums/c2...s/DSCN1674.jpg

I managed to borrow one SD from a friend and try it in the same SVGA CRT monitor that I did my tests. It is working fine. Didn't try to swap Mach chips and try like that. I also reinserted the AV9170 in a scary moment where the screwdriver that I used to lift the chip slipped to one side and the pins only went out from one side, not the other. Carefully removed it and put it back as you can see in the pics. Didn't have time to test it though.

Regarding replacing capacitors, it certainly needs someone experienced to do so because for the 3 capacitors behind the VGA socket to be replaced, that socket needs to be removed too and be put back.

Does anyone know if there are any people who can have a look at this for replacing capacitors. If they have knowledge on SDs it will be a plus. I will try and find someone here to be able to replace capacitors (however the last one he tried to replace the SMD capacitors in my A4000 board almost made it useless and had to send it to New Zealand) but I would like to know if there are any other solutions within the EU.

rkauer · 03 May 2011, 00:12

Can you wiggle those capacitors a bit with your fingers or using a small needle? Just to see if they have the solder loose.

Otherwise you'll have to replace the four capacitors. An electronic TV repair street shop can do this for you if you can't solder.

manicx · 03 May 2011, 15:43

I will try to do that. Yesterday I did some thorough testing. Specifically:

-I got the Mach chip from a working SD and installed it on mine=> Same result (I completely forgot to use the working SD with the new Mach I bought)...

-Waited 5 minutes for the SD to reach proper working temperature. The picture when in resolution 640 x 512 DblPal or 640 x 480 Multiscan is not blury. It is just too dark as if the contrast/brightness is really bad. When I switched to Pal High Res (640 x 256), the image seems distorted, I see almost half the screen moved to the right and it is like a puzzle with horizontal lines/pieces not aligned together. Same when I went to startup menu by clicking the two mouse buttons after booting the Amiga.

Another question... Does anyone know what each chip does on the MV1200 and especially the AV9170? I found a document but it is not a technical document.

FOL · 03 May 2011, 17:43

Quote:

Originally Posted by manicx

I will try to do that. Yesterday I did some thorough testing. Specifically:

-I got the Mach chip from a working SD and installed it on mine=> Same result (I completely forgot to use the working SD with the new Mach I bought)...

-Waited 5 minutes for the SD to reach proper working temperature. The picture when in resolution 640 x 512 DblPal or 640 x 480 Multiscan is not blury. It is just too dark as if the contrast/brightness is really bad. When I switched to Pal High Res (640 x 256), the image seems distorted, I see almost half the screen moved to the right and it is like a puzzle with horizontal lines/pieces not aligned together. Same when I went to startup menu by clicking the two mouse buttons after booting the Amiga.

Another question... Does anyone know what each chip does on the MV1200 and especially the AV9170? I found a document but it is not a technical document.

Sounds to me like the TDA8707H was damaged (aswell as mach chip) when you shorted the SD to the 23pin port.
You could have also damaged the memory chips too.

Hewitson · 04 May 2011, 13:53

Quote:

Originally Posted by manicx

Another question... Does anyone know what each chip does on the MV1200 and especially the AV9170? I found a document but it is not a technical document.

Google the datasheet.

26 March 2011, 18:15	#1
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	Dead EZ-VGA Scandoubler (external) Hello everyone My old friend, an extrernal EZ-VGA Scandoubler died today. A HDD failure (a crappy Hitachi 2.5" that almost got fire) made me try to unplug the mains from Amiga and the scandoubler was removed slightly and I heard a 'chuf'. I am not sure if I can fix this (I think a capacitor died). What alternatives do I have? Are there any external scandoublers sold these days? Crap day!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Internal Scandoubler for External Scandoubler	sbeehre	Swapshop	1	22 January 2008 10:29
1084S, VGA + scandoubler or LCD-TV?	candyman	support.Hardware	1	14 November 2007 12:17
AGA-VGA-Scandoubler questions	cybernoid	support.Hardware	6	06 February 2007 13:41
Does anyone have a spare VGA connector for a scandoubler....	ketma	support.Hardware	1	01 May 2005 08:57
FS: External Scandoubler	AMIGAZ	MarketPlace	12	05 April 2005 16:17

26 March 2011, 20:57	#2
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	It's worth a check inside the Amiga: when something plugged in the video port is sacked on live, the most common behaviour is a SMD resistor bit back of the video port get burned. Check the resistors prior to think your scandoubler is dead.

26 March 2011, 23:43	#3
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	Actually, I hooked the Amiga with a scart cable on a TV and it is working. I opened the scandoubler and one of the capacitors looks a bit lifted from the pcb.

27 March 2011, 04:01	#4
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	Does the SCART cable using both the +12 & +5V from the video port? Changes are that one of the power lines get its protection SMD resistor cracked.

27 April 2011, 16:22	#6
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	After a thorough look inside the scadoubler and with the help of AmigaKit tech department, I found that the Mach chip had a hole on it. Good thing is that I found a Mach chip replacement sold in AmigaKit. I replaced the old one and even though the SD is not dead now and it starts, the picture I get is blurry to the extend that it is unusable. The thing is that I don't know if the Mach chip I bought is pre-programmed. And second thing is that if it is, why is the image so blurry? I tried adjusting the little screw on the back of the SD but had no luck. If the Mach chip is not programmed, does anyone program such PLCC Mach chips? Really need help with this...

27 April 2011, 22:14	#7
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	The MACH chip is programmed (think of it like a big PIC chip). The blurry image may be from other problem (a bad capacitor or dodgy soldering somewhere).

28 April 2011, 11:54	#9
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	Thanks for your answers... I uploaded some images. I am trying to figure out some things but frankly, my knowledge on electronics is limited. My only suspicion may be on the SMD 22uF 16V capacitor above the Mach chip. It looks a bit lifted compared to the other ones. Some pics: http://i28.photobucket.com/albums/c2...s/DSCN1631.jpg http://i28.photobucket.com/albums/c2...s/DSCN1637.jpg http://i28.photobucket.com/albums/c2...s/DSCN1638.jpg I am not sure what to look on capacitors or other components. Any help with this is appreciated. I cannot see a similar 'hole' on any other chip and I am stuck a bit with this...

29 April 2011, 04:02	#10
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	I didn't see anything wrong from the pictures. Please pry out and reinsert the little AV9170 (A/D converter) into its socket and try again. Other than that, replacing the old capacitors is always a wise choice.

29 April 2011, 08:58	#11
Hewitson Registered User Join Date: Feb 2007 Location: Melbourne, Australia Age: 41 Posts: 3,772	The pin which is on the top left of the Mach in the first pic looks like it's bent.

29 April 2011, 10:19	#13
Hewitson Registered User Join Date: Feb 2007 Location: Melbourne, Australia Age: 41 Posts: 3,772	Yeah I agree, I wasn't suggesting it was the problem. Still worth taking a quick look at though IMO

29 April 2011, 11:15	#14
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	Thanks everyone. Aparently, these are pics before I replace the Mach. Sorry! I will make a new pic after the replacement. Basically, PLCC usually make contact around halfway to the socket, at least from what I have seen. But I suppose, I can try and lift each pin a bit with maximum caution and lots of patience. Right? I will also try and reinsert the AV9170. If the problem persists, I will try and see where I can replace the SMD capacitors since I can't do such thing myself.

29 April 2011, 12:09	#15
Loedown Precious & fragile things Join Date: Feb 2009 Location: Victoria, Australia Posts: 1,946	Blurry picture suggests one of the components has failed as opposed to a chip failure. Raised capacitors aren't an issue, when they are placed onto the boards it is possible that the leg(s) were slightly bent and as long as some part of both legs in within the bounds of the solder it will be fine. I have a limited understanding of scandoublers, but I have seen VGA monitors lose their focus ( if it's an old CRT type ). To me it sounds like a biasing issue on one of the chips, much the same as A4000 audio issues when a voltage rail is missing, the horrible distortion you get when the -12V signal isn't present for example.

02 May 2011, 11:51	#16
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	Some more pics with the new Mach. As you can see, it is a tight fit... http://i28.photobucket.com/albums/c2...s/DSCN1668.jpg http://i28.photobucket.com/albums/c2...s/DSCN1670.jpg http://i28.photobucket.com/albums/c2...s/DSCN1672.jpg http://i28.photobucket.com/albums/c2...s/DSCN1673.jpg http://i28.photobucket.com/albums/c2...s/DSCN1674.jpg I managed to borrow one SD from a friend and try it in the same SVGA CRT monitor that I did my tests. It is working fine. Didn't try to swap Mach chips and try like that. I also reinserted the AV9170 in a scary moment where the screwdriver that I used to lift the chip slipped to one side and the pins only went out from one side, not the other. Carefully removed it and put it back as you can see in the pics. Didn't have time to test it though. Regarding replacing capacitors, it certainly needs someone experienced to do so because for the 3 capacitors behind the VGA socket to be replaced, that socket needs to be removed too and be put back. Does anyone know if there are any people who can have a look at this for replacing capacitors. If they have knowledge on SDs it will be a plus. I will try and find someone here to be able to replace capacitors (however the last one he tried to replace the SMD capacitors in my A4000 board almost made it useless and had to send it to New Zealand) but I would like to know if there are any other solutions within the EU.

03 May 2011, 00:12	#17
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	Can you wiggle those capacitors a bit with your fingers or using a small needle? Just to see if they have the solder loose. Otherwise you'll have to replace the four capacitors. An electronic TV repair street shop can do this for you if you can't solder.

03 May 2011, 15:43	#18
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	I will try to do that. Yesterday I did some thorough testing. Specifically: -I got the Mach chip from a working SD and installed it on mine=> Same result (I completely forgot to use the working SD with the new Mach I bought)... -Waited 5 minutes for the SD to reach proper working temperature. The picture when in resolution 640 x 512 DblPal or 640 x 480 Multiscan is not blury. It is just too dark as if the contrast/brightness is really bad. When I switched to Pal High Res (640 x 256), the image seems distorted, I see almost half the screen moved to the right and it is like a puzzle with horizontal lines/pieces not aligned together. Same when I went to startup menu by clicking the two mouse buttons after booting the Amiga. Another question... Does anyone know what each chip does on the MV1200 and especially the AV9170? I found a document but it is not a technical document.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)