I do not understand the mod (Remove the Jumper line J19 on the analog board. Connect the input) Do you have an idea ??

1 reply [Last post]
Offline
Joined: Mar 14 2005
Posts: 22

I had made several attempts to power up my 6500's Takky-CC(which I have been building for the last 3 months)...
But no display Sad, I can hear the booting the sequence and everything, even heard it
says that my clock is in correct... I tried with the 3.3v regulator
and without it... Still, no display (screen is black).
I then plugged the LC580's mobo in and the CC screen came up fine. do you
think I have power supply issue? I think it is not enough power to
boot the screen.

Also, the wiring diagram
(http://homepage2.nifty.com/frogeye/takky.html) is so confusing...
(#1) The first part of the diagram says:

VGA display
Since 630 series logic boards support the VGA mode, the modification
to the VGA mode is recommended. In this section the procedure to the
VGA mode will be explained. Do not attach the analog board connector
cables to the monitor ID input S19 to S21 of the '630 connector'.
Connect S19 and S20 of the '630 connector' together and leave S21
open. Refer to the section of the analog board modification and the
screen adjustment of Mystic for the board modification and adjustment.

(#2) Then follow with this instructions:

Analog board modification
Caution: This chapter does not include the modification to the VGA mode.
The 630 series logic boards require -12 Volts of power supply to the
S1 pin. However, the boards do not use -12 Volts directly but regulate
-12 Volts to -5 Volts. So if the minus power supply more than -7 Volts
is satisfactory. The -10 Volts will be supplied through S1 pin by
modifying analog board.

Caution: Since the ordinary output of S1 pin of the analog board is -5
Volts, the the logic boards like ColorClassic / CC II or LC575 will be
broken by connecting an analog board modified with this method.

Remove the Jumper line J19 on the analog board. Connect the input
terminal, which is connected to LP14, of the negative voltage
regulator (L7905) at IP8 to the line from the S1 pin of the connector.

I'm lost now...
I did the connection jumper for S19 and S20 and left open on S21.
Then I remove it and just connected P20, P24, P25 of AB conn. to the S19, S20, S21 of 630 Conn.... still no displays.

I do not understand the mod in (#2): where it says...

"Remove the Jumper line J19 on the analog board. Connect the input
terminal, which is connected to LP14, of the negative voltage
regulator (L7905) at IP8 to the line from the S1 pin of the connector".

Do you have an idea?? Anyone have any pictures tutorial instructions of this part of the mod?
Any helps is greatly appreciated.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Offline
Joined: Dec 20 2003
Posts: 180
A few thoughts

It's so long since I made my Takky, and I no longer have it, so most of these suggestions and comments are rather provisional, but here goes. . . . .

I'm pretty certain that the problem is not the power supply; the fact that your Takky boots OK, with the clock issue mentioned, seems to confirm this.

So, either your 6500 board is producing a 'valid' signal, but your analogue board is not displaying it, OR your 6500 board is not producing a 'valid' video signal which the analogue board can use.

Ideally, I'd put the 6500 board in another Mac, and see what happens. If you can possibly do that, that's the best solution.

If not, it could be that the 6500 board is not producing a signal that the analogue board can show. For example, 1024 x 768, or even 640 x 480 at a 'wrong' frequency. To test for that, you could try connecting a monitor to the video output from the board - which may require some 'fiddling' around.

I suggest you check these issues before trying to debug your analogue board and its modifications.

Good luck!

Stuart

__________________

Stuart Bell,
Developer of the PowerCC site a long time ago.