Amiga A3000D Scan Doubler and Flicker Fixer trace repair due to leaking battery.

A3000T · Jan 10th 2023

I found many bad traces due to leaking battery. I used an oscilloscope to make sure I was getting the VC1 signal at FB485 from U204 (74F04) via Fat Agnus.

I then used an ohm meter to check R482, R483 (1 k), R470 (3.3k), R470 (1k pot phase adjust) resistors and the continuity going to them. I Jumper'd them on the back side of the mother board and used tape to hold them in place. I had no IC's or resistors that were bad. I now have a great picture using interlace screen modes. Now that I repaired the A3000D I ordered a Buddha IDE from icomp and get rid of my SCSI hard drive. I have a Buddha IDE in my A3000T. Now I can use a more reliable IDE hard drive or CD/DVD or SATA with an IDE to SATA adapter. My greatest need was a CD/DVD so I could load my 3.5, 3.9, 3.2 OS and other software that I have on CD. See schematic.

I hope this helps you making repairs.

Jens · Jan 10th 2023

Thanks - when doing a restoration like this, you have to know that the NE564 PLL is particularly piccy about it's external components. So much that even using a socket for the chip will change results. So the general recommendation is to keep the chip without a socket, unless you want to re-calculate and fine-adjust the external components.

A3000T · Jan 11th 2023

I didn't need to pull any chips. I know about NE564 and not to use a socket. by the way I found on ebay.com 7 NE564 IC's for $4.99 plus $3.88 shipping (see picture for your prices) not so pricy chip. The A1200 scan doubler / flicker fixer is working great! A word of advice...."IF IT AINT BROKE DONT FIXIT"!!

My A1200 system, Microbotics A1200 card with FPU and 8 megs ram (when the ram gets here), IDE to SD adapter with 8gb SD card, with IDE CD/DVD drive, I will be using a SATA CD/DVD drive as soon as the IDE to SATA adapter arrives, then I will have a SATA and power cables for the CD/DVD, much smaller.

.

A3000T · Jan 11th 2023

Correction A3000D scan doubler / flicker fixer is working great! I have been working on 3 Amigas they seem to run together at times.

A3000T · Jan 12th 2023

Jens

I got my Buddha IDE card and installed it in my A3000D and it is working great.

I have a CyberVision 64/3d. When I use the CV screen modes the screen comes up great but when I try to open a drive i.e. DH0 drive the screen locks up and then the mouse quits after about 5 seconds. I am using CV Version 3.0, the board tests ok with 256mb ram. It does it on the A3000T with MK 2 060 Buddha IDE and OS3.2. And the stock A3000D with Buddha IDE with OS3.2. Any idea what is causing this.

Jens · Jan 13th 2023

So the lockup only happens with CV64, but not with a native screen mode? I'd then say that the Cybervisiion software is having trouble. The Buddha software uses system resources and IRQ2, nothing else. Mouse locking up might be an indicator that an IRQ is not served. If the Cybervision card has a way to ise IRQ6 instead of IRQ2, I'd try that.

Note that I have never seen a Cybervision in real-life. When the P96 drivers were written, it was remote-tested to a large degree.

A3000T · Jan 15th 2023

Jens

Thanks for your reply. I removed the CV software and installed Picasso96 and gtlayout.lha and identify.lha all works well.

I thought problem might have been the CV board. The CV has 256megs of ram on it I wish some of it would be available for fast ram.

The only problem is finding a monitor that can handle all the modes. One way is to have two monitors or use a vga switch which I had but got rid months ago. I will keep looking for a good multi sync monitor under $30.00) and a vga switch ($5.00) at thrift stores. I bought the CV 64/3d when I bought my 3000T but was unable to get it to work back then. It works now! Thanks, again.