If I'm not mistaken VRA is a pull up resistor. On the mother board schematic
look right above D3 and you should see the resistors that create VRA and VRB
May be one of the SIP types, This line needs to be held high.
Take a 1K resistor, connect one end to +5 volts then touch the other end to
pin 1 of D5 with the resistor connected, pin 1 should read high.
If it does that means VRA is open and needs replacing
If it stays low then one of the IC's that connect to VBA has
a short. VBA connects to several IC's
Tim
-----Original Message-----
From: Kevin Moore
Sent: Oct 31, 2010 2:57 AM
To: rasterlist@vectorlist.org
Subject: Re: RASTER: SID Graphics problem
Ok. As for relay, the daughter board I have is labeled UR and pin 12 of the header is not connected. Also the Dip switches appear to be wired different than the UR.
I've been going through with a probe, and I have come up with a question. What is the VRA line. Most notably on D5 of the motherboard board pins 1, 9, 7, 10 VRA is low, I'm thinking it should be pulsing. But I could be wrong. So far I've been unable to find where it comes from on the schematics.
Kevin
On Fri, Oct 29, 2010 at 4:05 PM, teeray
<teeray@earthlink.net> wrote:
Yes, the only thing I can think of is pin 15 of E5 must be pulsing.
But I don't think the relay would be fast enough to keep up ?
Maybe so.
I'm thinking flip is low so it draws the score at bottom and reversed
just before it starts to draw the invaders flip goes high so they
are drawn correctly then just before it gets to the bases flip goes low
again causing the bases to be drawn at the top of screen and reversed
Base is upside down and reversed (correct for player two)
Invaders are correct (correct for player one)
Score is upside down and reversed (correct for player two)
-----Original Message-----
From: Kevin Moore
Sent: Oct 29, 2010 8:32 PM
To:
rasterlist@vectorlist.org
Subject: Re: RASTER: SID Graphics problem
Well so far I haven't come up with anything but then I haven't had 5 mins to sit down with it again.
I completely forgot about the relay on the yoke. The might explain the backwards text. I hope to get a little more time in the next day to sit down and check the decoders.
Thanks for the suggestions. I really don't do much with raster games so this is a bit new to me.
Kevin
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Received on Mon Nov 1 11:51:22 2010