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Author Topic: Enterprise does not power on anymore (Read 6494 times)

Offline edoz

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Enterprise does not power on anymore
« on: 2015.December.18. 14:46:37 »
Dear All. I have a problem. My Enterprise machine does not power up anymore :( I have only one machine .. and for me this is a bad thing as i cannot test SymbOS applications anymore on the real hardware. I have no idea what is going on.


Maybe someone can help me. I have no idea why. The machine was just on my desk all the time without any troubles.

The problem:

If i put the power plug inside the enterprise nothing happens. The RED LED is burning but i have no output picture on my monitor.
Normally you can hear the keyboard sound after a while if you press a key but this is not happening. I only have a black screen on the monitor and that's it. if i power on the system i hear a small 'click' from the speaker. (but that is normal i think)

Maybe.. but I'm not sure anymore i have inserted the monitor cable the wrong way (up side down) But I'm not sure if this can harm the machine. Anyway i think it as it could be that i did it but because i can't remember it anymore I notice it here, as maybe i did it ;)

Other thing is that i did a (volt) measurement on the adapter, which gives me a -12,2 output. On the adapter it is saying that it is 9.5 V so for me this is a bit strange. But I'm not sure what + and - is. (so it could be just +12,2) I have the feeling that the power plug inside part is the - and the outside mantel is the + ?. (But you cannot see it on the adapter)

Other thing is (I'm not an electronic expert) i have this BEEP sound on my multimeter to see if there is a connection between 2 points. If i power off the power adapter and i put  the + and - on the  + and - of the the powerplug it beeps ? (that is not good not?) So maybe i can replace the adapter with an other one but i need to be sure before doing that what is + and what is -

Do you have any suggestions?
 
Have fun with the Z80!

Offline Zozosoft

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Re: Enterprise does not power on anymore
« Reply #1 on: 2015.December.18. 15:05:19 »
The inner are the negative on the power plug. Higher voltage without load are normal.

The monitor are old CRT or modern LCD? (Modern monitors don't display the broken picture, then you can't see the some lifesign.)

If I remember right you have a turbo machine. Change the CPU speed change anything?

Are you expert in electronics?

Offline Zozosoft

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Re: Enterprise does not power on anymore
« Reply #2 on: 2015.December.18. 15:07:46 »
And do you have any external expansion (EXDOS card, SD interface, etc). If yes then try to remove these.

Offline edoz

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Re: Enterprise does not power on anymore
« Reply #3 on: 2015.December.18. 15:14:09 »
HI Zozosoft!

No i use this old Philips CRT monitor (CM8833). But is shows nothing. Indeed i have the turbo inside. Switching between CPU speed those not do anything. No I'm not an hardware expert. But i can do some measurements with my multimeter.

Is there something else i can measure ? I have this digital multimeter fx-99mx.

So if i understand you right it seems that the power supply works fine then.

But normally you must have sound from the keyboard not? I have the SD card which i removed also. But that doesn't do anything unfortunately.
Have fun with the Z80!

Offline edoz

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Re: Enterprise does not power on anymore
« Reply #4 on: 2015.December.18. 15:28:11 »
if i measure the voltage wile the machine is plugged and running it is indeed 9,34 V
Have fun with the Z80!

Offline Zozosoft

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Re: Enterprise does not power on anymore
« Reply #5 on: 2015.December.18. 15:29:34 »
No i use this old Philips CRT monitor (CM8833). But is shows nothing.
Right input selected? :-)
And the monitor cable now in the right position?

At the most of time when Enterprise not starting, the Nick display some random screen garbage on the screen.
The totaly nothing sound very bad :cry:


Quote
Is there something else i can measure ?
Check the +5V at the joystick ports and at the cartridge socket. +12V at the monitor connector (mode switch signal).
Do it carefully, don't short circuit anything with the multimeter probes.

Offline edoz

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Re: Enterprise does not power on anymore
« Reply #6 on: 2015.December.18. 15:35:35 »
No. i selected the right input on the monitor. So i'm sure about that..

I'm not a hardware expert but i can  build in a 7 MHZ kit inside my MSX. I can solder a bit if there is a schematic for it ;)
And i can do some measurements. I will do it carefully.

Between Which PINS i must measure ? Could you give me some hint on that ?
Have fun with the Z80!

Offline edoz

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Re: Enterprise does not power on anymore
« Reply #7 on: 2015.December.18. 15:38:35 »
BDW: You always have this sound from the keyboard not ?? (even if i have no display)
Have fun with the Z80!

Offline edoz

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Re: Enterprise does not power on anymore
« Reply #8 on: 2015.December.18. 15:45:15 »
I have on the Controlports 1 and 2, (5V between pin 1 and 2) ( if you look from the back of the machine and it's about the pins on the top)

I have also on the Videoport 12V between pin 2 and 6 from top looked from the back.
Have fun with the Z80!

Offline Zozosoft

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Re: Enterprise does not power on anymore
« Reply #9 on: 2015.December.18. 15:51:08 »

Offline Zozosoft

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Re: Enterprise does not power on anymore
« Reply #10 on: 2015.December.18. 15:54:20 »
Normally you can hear the keyboard sound after a while if you press a key but this is not happening.
Yes, normally you can hear the key click.

Offline endi

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Re: Enterprise does not power on anymore
« Reply #11 on: 2015.December.18. 15:59:43 »
Yes, normally you can hear the key click.

if wp or basic or exdos etc started
A diplomás magyar programozó megcsinált egy pacmant egy év alatt, majd lefikázta a világ legjobb játékait. :D

Offline Zozosoft

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Re: Enterprise does not power on anymore
« Reply #12 on: 2015.December.18. 16:00:44 »
And i can do some measurements. I will do it carefully.
Try to measure the RESET pin on the system bus. Normaly it is on +5V, and pressing reset make a 0V pulse.
If it is on constatly 0V then very bad news, it is means the Dave not running :-(

More measurement need a scope.

Offline edoz

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Re: Enterprise does not power on anymore
« Reply #13 on: 2015.December.18. 16:01:08 »
I don't get it . I was just do measurements and spontaneously the Enterprise is STARTING!!
How good that be?!
Have fun with the Z80!

Offline Zozosoft

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Re: Enterprise does not power on anymore
« Reply #14 on: 2015.December.18. 16:01:49 »
if wp or basic or exdos etc started
First key click at the ENTERPRISE screen! :-)