Heyo, No idea if this group is still active, but I'll give it a shot considering I have run out of ideas.looking for broken traces, vias and bodge wires and found none.
I have a 7300 in my possession, it powers up with fans spinning and I can hear the harddrive being accessed but the CRT lights up to a solid green screen. And I have already reseated all my socketed chips, including the CPU, and traced my connections
The computer did have loading bars when I originally acquired it, but has since refused to do anything but give a solid green screen.
My question is: What are my options at this point? And is there any fix for this that I haven't tried yet?
Any and all ideas are welcome, I'm at the end of my rope with it as of now.
Thanks, CRD.
The floppy drive seems to function, but I don't have any floppies.
On Friday, December 27, 2019 at 7:36:05 PM UTC-5, CRD wrote:forgetting that, d'oh.
The floppy drive seems to function, but I don't have any floppies.
So when you say "solid green screen", is it truly solid, or is it a bunch of horizontal lines with some small gaps?
I just powered mine up for the first time in several years, and that's what it did. :-/ However, I let it sit for 30 minutes, and then power cycled it, and it came up fine. :-)
So, before we get out oscilloscopes to find out what parts in the power supply on on the moboard are marginal, you might try letting it warm up like I just did.
You are also going to need the admin boot floppy to facilitate trouble-shooting, and so you can park the hard disk's heads before moving the machine. Early MFM drives did not auto-park on power off, and I destroyed the first drive in this machine
On Saturday, December 28, 2019 at 12:21:10 PM UTC-5, Peter Schmidt wrote:forgetting that, d'oh.
On Friday, December 27, 2019 at 7:36:05 PM UTC-5, CRD wrote:
The floppy drive seems to function, but I don't have any floppies.
So when you say "solid green screen", is it truly solid, or is it a bunch of horizontal lines with some small gaps?
I just powered mine up for the first time in several years, and that's what it did. :-/ However, I let it sit for 30 minutes, and then power cycled it, and it came up fine. :-)
So, before we get out oscilloscopes to find out what parts in the power supply on on the moboard are marginal, you might try letting it warm up like I just did.
You are also going to need the admin boot floppy to facilitate trouble-shooting, and so you can park the hard disk's heads before moving the machine. Early MFM drives did not auto-park on power off, and I destroyed the first drive in this machine
Thank you for the input.
It is truly solid. Photo here:
https://i.redd.it/0i62yx3dhl841.jpg
-OR- https://www.reddit.com/user/RetroProcessor18/comments/eji8hx/att_unix_pc_7300_power_up/
I will double check and let the computer run for a time.
I am also concerned as when I acquired the computer it at least started running the loading bars, the hard drive spins up, but I do not know if it is damaged. I do have an adapter board to replace the hard drive in the future.
I have a 7300 in my possession, it powers up with fans spinning and I
can hear the harddrive being accessed but the CRT lights up to a solid
green screen. And I have already reseated all my socketed chips,
including the CPU, and traced my connections looking for broken traces,
vias and bodge wires and found none.
The computer did have loading bars when I originally acquired it, but
has since refused to do anything but give a solid green screen.
My question is: What are my options at this point? And is there any fix
for this that I haven't tried yet?
Any and all ideas are welcome, I'm at the end of my rope with it as of now.
Thanks, CRD.
My question is: What are my options at this point? And is there any fix
for this that I haven't tried yet?
Heyo, No idea if this group is still active, but I'll give it a shot considering I have run out of ideas.looking for broken traces, vias and bodge wires and found none.
I have a 7300 in my possession, it powers up with fans spinning and I can hear the harddrive being accessed but the CRT lights up to a solid green screen. And I have already reseated all my socketed chips, including the CPU, and traced my connections
The computer did have loading bars when I originally acquired it, but has since refused to do anything but give a solid green screen.
My question is: What are my options at this point? And is there any fix for this that I haven't tried yet?
Any and all ideas are welcome, I'm at the end of my rope with it as of now.
Thanks, CRD.
On Friday, January 3, 2020 at 12:15:55 PM UTC-5, CRD wrote:forgetting that, d'oh.
On Saturday, December 28, 2019 at 12:21:10 PM UTC-5, Peter Schmidt wrote:
On Friday, December 27, 2019 at 7:36:05 PM UTC-5, CRD wrote:
The floppy drive seems to function, but I don't have any floppies.
So when you say "solid green screen", is it truly solid, or is it a bunch of horizontal lines with some small gaps?
I just powered mine up for the first time in several years, and that's what it did. :-/ However, I let it sit for 30 minutes, and then power cycled it, and it came up fine. :-)
So, before we get out oscilloscopes to find out what parts in the power supply on on the moboard are marginal, you might try letting it warm up like I just did.
You are also going to need the admin boot floppy to facilitate trouble-shooting, and so you can park the hard disk's heads before moving the machine. Early MFM drives did not auto-park on power off, and I destroyed the first drive in this machine
the right places without the case on, but it surely must be doable. Once overheated, I needed to leave it off for like 20 minutes before powering back on, inside the case.Thank you for the input.
It is truly solid. Photo here:
https://i.redd.it/0i62yx3dhl841.jpg
-OR- https://www.reddit.com/user/RetroProcessor18/comments/eji8hx/att_unix_pc_7300_power_up/
I will double check and let the computer run for a time.
I am also concerned as when I acquired the computer it at least started running the loading bars, the hard drive spins up, but I do not know if it is damaged. I do have an adapter board to replace the hard drive in the future.
This may not be the root cause of the green screen, but the 3B1/7300 will overheat after some smallish number of minutes running with the case off. Mine would go catatonic after as little as 10 minutes. I never managed to get enough cooling air in
If you can get a cellphone recording of the hard drive noises at power up, I can opine on its health. Put the mic right at the base of the monitor.
—Peter
P.S. Here’s mine right now, running the Office, the Programmer’s Calculator, and GNU emacs :-)
https://drive.google.com/open?id=1gLeI4Pc8qiKR3km_RuMXfiwqMBYPMv0h
On Thursday, December 26, 2019 at 8:20:17 PM UTC-8, CRD wrote:looking for broken traces, vias and bodge wires and found none.
Heyo, No idea if this group is still active, but I'll give it a shot considering I have run out of ideas.
I have a 7300 in my possession, it powers up with fans spinning and I can hear the harddrive being accessed but the CRT lights up to a solid green screen. And I have already reseated all my socketed chips, including the CPU, and traced my connections
Iowa.The computer did have loading bars when I originally acquired it, but has since refused to do anything but give a solid green screen.
My question is: What are my options at this point? And is there any fix for this that I haven't tried yet?
Any and all ideas are welcome, I'm at the end of my rope with it as of now.
Thanks, CRD.
CRD, may I ask where you are located? I have a large cache of AT&T Unix PC Parts, and I might be able to help you diagnose... If you are close enough to me, I could be persuaded to make a house call. I split my time between Las Vegas and Central
On Friday, January 3, 2020 at 3:05:01 PM UTC-5, pe...@transcend.aero wrote:machine forgetting that, d'oh.
On Friday, January 3, 2020 at 12:15:55 PM UTC-5, CRD wrote:
On Saturday, December 28, 2019 at 12:21:10 PM UTC-5, Peter Schmidt wrote:
On Friday, December 27, 2019 at 7:36:05 PM UTC-5, CRD wrote:
The floppy drive seems to function, but I don't have any floppies.
So when you say "solid green screen", is it truly solid, or is it a bunch of horizontal lines with some small gaps?
I just powered mine up for the first time in several years, and that's what it did. :-/ However, I let it sit for 30 minutes, and then power cycled it, and it came up fine. :-)
So, before we get out oscilloscopes to find out what parts in the power supply on on the moboard are marginal, you might try letting it warm up like I just did.
You are also going to need the admin boot floppy to facilitate trouble-shooting, and so you can park the hard disk's heads before moving the machine. Early MFM drives did not auto-park on power off, and I destroyed the first drive in this
the right places without the case on, but it surely must be doable. Once overheated, I needed to leave it off for like 20 minutes before powering back on, inside the case.Thank you for the input.
It is truly solid. Photo here:
https://i.redd.it/0i62yx3dhl841.jpg
-OR- https://www.reddit.com/user/RetroProcessor18/comments/eji8hx/att_unix_pc_7300_power_up/
I will double check and let the computer run for a time.
I am also concerned as when I acquired the computer it at least started running the loading bars, the hard drive spins up, but I do not know if it is damaged. I do have an adapter board to replace the hard drive in the future.
This may not be the root cause of the green screen, but the 3B1/7300 will overheat after some smallish number of minutes running with the case off. Mine would go catatonic after as little as 10 minutes. I never managed to get enough cooling air in
and a faint squealing on spin down. Both can be heard in the video I have linked below.If you can get a cellphone recording of the hard drive noises at power up, I can opine on its health. Put the mic right at the base of the monitor.
—Peter
P.S. Here’s mine right now, running the Office, the Programmer’s Calculator, and GNU emacs :-)
https://drive.google.com/open?id=1gLeI4Pc8qiKR3km_RuMXfiwqMBYPMv0h
Thank you for the input Peter. I have yet to close up the machine back into it's housing, but I did record the spin up and spin down of the hard drive. It doesn't sound good, but I'm not entirely sure what I am listening for. I hear movement on spin up
https://www.reddit.com/user/RetroProcessor18/comments/ew6p81/att_unix_pc_mfm_hard_drive_power_up_power_down/
-CRD
Sysop: | Keyop |
---|---|
Location: | Huddersfield, West Yorkshire, UK |
Users: | 296 |
Nodes: | 16 (2 / 14) |
Uptime: | 46:56:59 |
Calls: | 6,648 |
Files: | 12,198 |
Messages: | 5,329,919 |