Quadra 950 no video but chime sound -

[dssence]

So I just came across this wonderful forum. I'm from Argentina, I've had many computers since my childhood and yesterday I found dropped in the street a Quadra 950, with it's monitor but without keyboard. I managed to switch it on , (I didn't know it had a power button on it's keyboard). So I swtiched the key and it automatically turned on. plugged the monitor and no image. So I thought well monitor crt tube might be dead. I opened it and inspected the screen on the flyback adjusted and had still power and brightness. So didn't think monitor could be bad.
At the same time what called my attention was once I disconnected the DB15 video connector machine initialized made the chime sound.. seemed it booted into the system and made another melody. So my question is , I want to try with another monitor.. something might be wrong.. I inspected inside all simms for bad contacts. I checked the lithium battery has no voltage.
Then as I'm myself a repair technician on cellphones and microsolderign. I thought about making a cable for PC monitor. I checked some of the schematics.. but still had no image.. but again what calls my attention is eveytime I unplug db15 I hear the chime noise.. I know from information I read this is really finicky about sensing the monitor data.. but I assume it has something to do with it. I don't have a deep knowledge about quadras so that's why I'm posting in here for help. I don't have the machine original keyboard. , might I replace with a pc keyboard? also pc mouse.. ?
Thanks so much

 

[cheesestraws]

seemed it booted into the system and made another melody

What did the other melody sound like? Can you upload it somewhere? That sounds like it might be actually an error chime, in which case the computer might have bad RAM.

 

[dssence]

I've been awake all night trying to check some different pinout variations on db15 connector. somehow I plugged the original mac monitor unplugged it then plugged a pc samsungsynmaster and I had image but in a different tone variation. So I'm suspecting the original mac monitor is not working but is setting the video card to output video.. I think something has to do with it. If not I wouldnt have got video .. Do you know the exact pinouts to adapt a normal pc or lcd monitor ?

 

[dssence]

will these pinouts work with a normal CRT pc monitor , or it has to be multy sync like nec

"You can pretty much ignore the ID bits. You can try the following cable
pinouts to match to a VGA connector."

Mac Video DB15 VGA Connector HD15
---------------- --------------------

2 ------------------- Red Video ------------ 1
1 ------------------- Red Ground ----------- 6
9 ------------------- Blue Video ----------- 3
13 ------------------- Blue Ground ---------- 8
5 ------------------- Green Video ---------- 2
6 ------------------- Green Ground --------- 7
15 ------------------- Hsync ---------------- 13
12 ------------------- Vsync ---------------- 14
14 ------------------- Sync Ground ---------- 10