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Old 16 November 2018, 00:26   #1
Triple
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untouched a1200 85mb rev 2b deluxe edition help please

ok if you look left youll notice this is my first post so you know there is going to be a problem in here

Ok firstly hello every body .


so just by random i stumbled upon a video on youtube and it got my juices flowing of course it was a video about amiga's

back in the day i used my machine to mainly play games but i kept getting issues floppy disks failing and my hdd every 2-3 days needing a fresh install this was around the time amiga went bust shops were shutting down everything became hard to get hold of unless thru amiga magazines i had the option to buy the very best blizzard board but at about £600 at the time was more than 2 times what i paid for my amiga a1200 so instead i brought the ami tek 8mb with no fpu or crystal i understand this card does affect your chances to get the pcmcia to work but at this time i didnt use it anyway so it dint matter (is this what ppl mean by a timing fix and would i need this with my setup ) anyway growing ever tired of having to do this evry other day i put said machine in the loft until i watched this video suddenly all my needs that i needed way back in the 90's have now become available so 3 days ago i got up to the loft get the amiga out all seems good yep just as i left it with the top unscrewed for ease of access i honestly cant remember ever having it screwed together so with thoughts of cf-ide no cable 16gb hdd and a recapping in mind to finally cure this problem i took the top off keyboard unplugged shielding removed to give it the ounce over very happy to see none of the caps have split and caused damage ... but i know why the top is off and its been up in the loft for 20+ years there must have been a reason .. anyway after researching and buying the cf-ide no cable version and a sandisk ultra 16gb and some new caps for less than £40 im thinking wow summit to show the grand children ... i was wrong it powers up fine but i get no picture just a grey screen after dong more research i then stripped it all the way back to just a power supply connected to the motherboard but then i couldnt see any activity as i had no lights attached so powered off re-plugged the top of the amiga in so i had floppy hdd and power lights showing and sure enuff the green power light is on very bright (good sign) but still no picture at this point im thinking of buying a new rgb-scart lead as my final attempt to get a picture (more about that later ) anyway 4-5 hours later motherboard totally out nothing connected and very powerful magnifying glass looking at this thing and reading what other ppl have said about this possible problem i think ive spotted something in pin 4-5 on a picture im gunna try and upload later to show you

do you think there is even a problem and it lies with this picture or something else ?.

http://eab.abime.net/attachment.php?...1&d=1542323399

ok on to the rgb-scart whitch is the better version of this cable ?.

https://www.ebay.co.uk/itm/250786119867 EDITED i contacted this seller as iscclearly says hand made with a request that he make me a 5m version at a highter price of course altho he did get back to me very quickly he said he couldnt do it (whitch i thourght strange )

https://amigakit.amiga.store/product...roducts_id=226 EDITED im very silly here my link shows the cable i wanted but i needed a longer version under this item is links to longer versions but there website dont show all them in image for just in links in tiny print at the bottom of this version anyway i saw it cursed at myself and then tried to buy 1 ... omg just to find out you need to REG first ok so i done that got a bot msg saying an e-amail would be sent winthin an hour BLAH BLAH anyway 3 hours later im still waiting for this comfermation e-mail i tried to buy thiscable and it declined my credit card 3 times in a row so im guessing the bot can send you a mail but a human has to enable the account how very annoying . .. online shooping is like waiting in a que on black friday it seems

i could do with a 5m version tho but cant find one atm

and also going back a while ago i mentioned the amitek 8mb card that i have

http://eab.abime.net/attachment.php?...1&d=1542323569

again back in the 90's to get the crystal and fpu was very expensive i understand that now there are very cheap could anybody advise me what fpu and crystal i would need and that are compatable with this card .

and finally some of the bits i was looking forward to putting in my system but after more research have decided that this is a job for someone like the user AmigaPassion http://eab.abime.net/member.php?u=66922 would be better at doing and his close ish distance to myself


http://eab.abime.net/attachment.php?...1&d=1542323569

with the ease of getting all amiga games now if i could get this amiga working with all its nice new bits would be amazing and it wont just end up back in the loft for another 20 years it could retake its rightful place under my tv in the living room again (RANT OVER ) sorry i went on a bit but the more info you have the better i think . any questions welcome .
Attached Thumbnails
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Name:	ami tek 8mb no fpu or crystal.jpg
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Name:	cf-ide no cable.jpg
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ID:	60829  

Last edited by Triple; 17 November 2018 at 03:57.
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Old 16 November 2018, 07:07   #2
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this is a quote taken from zetr0 posted on november 13th 2006

http://eab.abime.net/showthread.php?t=30757

i might have gotten the wrong end of a sharp stick here but could i try and get hold of the pcmcia ram he is talking about and set my acc card to 4mb and as this is also made by amitek and by setting mine from 8mb to 4mb would this work ie 4mb in pcmcia and 4mb in my trapdoor then try and get the fpu and crystal ?.


opps ive just read this back to myself and it dont make sense as i already have 8mb on my acc all im doing is still ending up with 8mb lol .its early ive been up all night forgive me hahaha.
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Old 16 November 2018, 21:15   #3
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You can test the video using a simple CINCH cable connected to the yellow cinch output (composite). Most TVs have composite inputs. That would rule a the cable issue and it's easy, you probably have audio CINCH cables at your home.

Does the floppy drive click? if it does, the amiga probably ROM booted. If it doesn't, well, not a good sign.

Also you could try to boot a demo to see if there's sound.

I totally suck at electronics, but you have to be scientific with those.

If you can make that work, a A1200 + 8MB is a perfect machine for whdload gaming. No need for a 68040. Memory is the key.
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Old 16 November 2018, 21:46   #4
Triple
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Quote:
Originally Posted by jotd View Post
You can test the video using a simple CINCH cable connected to the yellow cinch output (composite). Most TVs have composite inputs. That would rule a the cable issue and it's easy, you probably have audio CINCH cables at your home.

Does the floppy drive click? if it does, the amiga probably ROM booted. If it doesn't, well, not a good sign.

Also you could try to boot a demo to see if there's sound.

I totally suck at electronics, but you have to be scientific with those.

If you can make that work, a A1200 + 8MB is a perfect machine for whdload
gaming. No need for a 68040. Memory is the key.


ah then i have a problem as i have tried the audio wire in the yellow socket and i just get the grey screen and my floppy drive does not make a noise i have not got any demo's lol i was more of a disk party person however i have some game installs or games that might boot so far all that i have tried have not made a noise or booted tho . if i plug the floppy hdd and power light 4 pin connector in it is a constant bright green .
am in contact with @AmigaPassion atm about a recap and fault finding fix for this machine

i know it used to fast back in 96 but with all the above issues thats why it had to go to the loft for so many years .

Last edited by Triple; 16 November 2018 at 23:32.
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Old 16 November 2018, 23:42   #5
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the alternative is to get a new/remade A1200 board (ReAmiga). The board isn't the rarest part. The rarest part is ... the rest
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Old 17 November 2018, 00:17   #6
Triple
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Quote:
Originally Posted by jotd View Post
the alternative is to get a new/remade A1200 board (ReAmiga). The board isn't the rarest part. The rarest part is ... the rest
yeah like i said i think @AmigaPassion has said he would take a look at it his works looks fantastic i guess i wont know until he has had a good look at it im no expert at this but like i said in my first post i looked at this thing for a good 4-5 hours under a magnifying glass before i even plugged anything in as i knew it was in pieces in my loft for some good reason . cheers for your help - advice

dave
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Old 26 November 2018, 18:20   #7
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Hi Triple,

Did not see anything wrong with any of the pins in your picture. You probably need to circle the pins you suspect and get a higher magnification picture of those pins.


a) If you have access to a digital voltmeter, I suggest you carefully check the voltages being supplied by your Amiga power supply for your A1200 when connected to your A1200. The three power pins should read fairly close to 5V, 12V and -12V under load.

b) If you are going to replace the electrolytic capacitors on your motherboard yourself, be very careful of how long you heat the component leads, components and PCB for.
I'd suggest you:
i) use a black (UV) light to look for and document signs of leaked electrolytic capacitor fluid on the board before you start.
This will make it easier for you to locate and fix any damage later after the old capacitor has been removed and before the replacment is installed.
ii) wear safety goggles and/or face shield as the old electrolytic capacitors have been known to explode when heated.
The fluid from electrolytic capacitors is corrosive as well.
iii) temporarily shield and protect all the other surrounding components from heat with wide aluminium tape
iv) add new lead based solder and flux to the solder joints about to be desoldered.
The new solder and flux will make it easier to melt the old solder.
v) use a small fine tipped soldering iron
vi) use a new desoldering braid wick for cleanup
vii) carefully clean arround the removed component with isopropyl alcohol and look for corrosion damage to fix while you have room for access.

Also, be very careful near the video bandpass filters and delay line components (Z221 and Z222) as heat can easily damage these now irreplaceable components. They are no longer being made!


The following links may be of help:

1) Amiga boot error code decoding: (http://wiki.classicamiga.com/Amiga_b...r_code_colours )

2) Link to manual for your Ami tek expansion card (http://amiga.resource.cx/manual/Amitek_Hawk.pdf).

Please note that there is no ram hard installed on the Ami tek card; you have to add it yourself by installing an appropriate 72-pin SIMM card in the SIMM slot on the back of your Ami Tek A1200 card. To work the 72-pin SIMM RAM card will need to have a rated access time of 80ns (nanoseconds) or lower and be of 1MB, 2MB, 4MB or 8MB in size.

Using an 8MB SIMM in the Ami tek card may affect your A1200's access to a peripheral card in the PCMCIA slot. The PCMCIA slot needs a free 4MB window of the A1200 68EC020's 16MB addressable memory space for operational access!

According to the manual, if you want a FPU then you'll need a PLCC version of either a 68881 or preferably 68882 FPU. If you have an FPU installed without the corresponding crystal then the FPU will operate at the A1200 default clock of only 14.3MHz when a FPU instruction is executed.

Jonathan
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Old 28 November 2018, 02:50   #8
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Quote:
Originally Posted by jlin_au View Post
Hi Triple,

Did not see anything wrong with any of the pins in your picture. You probably need to circle the pins you suspect and get a higher magnification picture of those pins.


a) If you have access to a digital voltmeter, I suggest you carefully check the voltages being supplied by your Amiga power supply for your A1200 when connected to your A1200. The three power pins should read fairly close to 5V, 12V and -12V under load.

b) If you are going to replace the electrolytic capacitors on your motherboard yourself, be very careful of how long you heat the component leads, components and PCB for.
I'd suggest you:
i) use a black (UV) light to look for and document signs of leaked electrolytic capacitor fluid on the board before you start.
This will make it easier for you to locate and fix any damage later after the old capacitor has been removed and before the replacment is installed.
ii) wear safety goggles and/or face shield as the old electrolytic capacitors have been known to explode when heated.
The fluid from electrolytic capacitors is corrosive as well.
iii) temporarily shield and protect all the other surrounding components from heat with wide aluminium tape
iv) add new lead based solder and flux to the solder joints about to be desoldered.
The new solder and flux will make it easier to melt the old solder.
v) use a small fine tipped soldering iron
vi) use a new desoldering braid wick for cleanup
vii) carefully clean arround the removed component with isopropyl alcohol and look for corrosion damage to fix while you have room for access.

Also, be very careful near the video bandpass filters and delay line components (Z221 and Z222) as heat can easily damage these now irreplaceable components. They are no longer being made!


The following links may be of help:

1) Amiga boot error code decoding: (http://wiki.classicamiga.com/Amiga_b...r_code_colours )

2) Link to manual for your Ami tek expansion card (http://amiga.resource.cx/manual/Amitek_Hawk.pdf).

Please note that there is no ram hard installed on the Ami tek card; you have to add it yourself by installing an appropriate 72-pin SIMM card in the SIMM slot on the back of your Ami Tek A1200 card. To work the 72-pin SIMM RAM card will need to have a rated access time of 80ns (nanoseconds) or lower and be of 1MB, 2MB, 4MB or 8MB in size.

Using an 8MB SIMM in the Ami tek card may affect your A1200's access to a peripheral card in the PCMCIA slot. The PCMCIA slot needs a free 4MB window of the A1200 68EC020's 16MB addressable memory space for operational access!

According to the manual, if you want a FPU then you'll need a PLCC version of either a 68881 or preferably 68882 FPU. If you have an FPU installed without the corresponding crystal then the FPU will operate at the A1200 default clock of only 14.3MHz when a FPU instruction is executed.

Jonathan
cheers thats very very helpful im very sure im getting no power to the motherboard now as i cant get any picture at all with an rf lead in yellow or then reboot then brown socket also i brought an amigakit scart to rgb off of amiga kit still no picture or with bare bones reboot not getting a beep for flopy or even a insert disk so no picture but the power pack is powering the motherboard anyway thats off to the menders for an expert to recapp it when and if he can find the power up - boot fix about my ami-tek 8mb trapdoor expansion card that i have i do have it et to 8mb i have the ram i used to use it 25 years ago all running fine .. just need some more clarity about the 4mb-8mb running modes . i never needed the pcmcia slot years ago so it didnt worry me but am i getting this right if i get someone to do a timming fix on my motherboard (i have the rev 2b motherboard ) can i still run it in 8mb mode and have the pcmcia slot working 100% ?. or with my rev 2b motherboard did that fix allready happen ?. about my ami-tek with 8mb what doea the fpu and crystal do ?. im just useing it for games would it make it better and also as i look at my expansion card i think the fpu is just a push in and use fitting ?. and the crystal is mebe 2 solders ?. is this correct ?. if so where can i by these from and roughtly how much are they ?.
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Old 29 January 2019, 21:56   #9
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She is fixed :-)

I'm happy to say this Amiga 1200 has been repaired, I have put a brief post up on Instagram with photos:

https://www.instagram.com/p/BtO3neOF...on_share_sheet


Issue? Rom sockets.
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Old 30 January 2019, 02:08   #10
Triple
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Quote:
Originally Posted by AmigaPassion View Post
I'm happy to say this Amiga 1200 has been repaired, I have put a brief post up on Instagram with photos:

https://www.instagram.com/p/BtO3neOF...on_share_sheet


Issue? Rom sockets.
thank you very much steve fantastic job m8 ... cant wait to get her back
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