TS 2068 Video Problem
15 messages · 2013-02-21 → 2013-04-28 · Yahoo Group era · View archive on archive.org
Participants: mark_ull, unbonnevie, Eduardo Fuentes, Rod H
Preserved from the Timex/Sinclair 2068 Yahoo Group (2001–2019), which is no longer online. Text reproduced from the archive.org archive; email addresses masked.
Messages
1. TS 2068 Video Problem
mark_ull · Thu, 21 Feb 2013 09:59
Hello,
I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
Thanks,
Mark
2. Re: [ts2068] TS 2068 Video Problem
Eduardo Fuentes · Fri, 22 Feb 2013 12:18
Hi Mark,
I think that the possible causes are:
Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
Faulty LM1889, it is located inside the modulator box.
Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
Regads,
Eduardo.
________________________________
De: mark_ull <[email]>
Para: [email]
Enviado: jueves, 21 de febrero de 2013 6:59
Asunto: [ts2068] TS 2068 Video Problem
Hello,
I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
Thanks,
Mark
3. Re: TS 2068 Video Problem
mark_ull · Sat, 23 Feb 2013 02:48
Thanks Eduardo.
I am opening up the machine. I see a flex cable connecting keyboard (top shell) to the main board. Is it safe to pull the cable out of the connector on the main board? It seems to fit in very tight to the connector.
--- In [email], Eduardo Fuentes <fuentesea@...> wrote:
>
> Hi Mark,
> I think that the possible causes are:
> Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
> Faulty LM1889, it is located inside the modulator box.
> Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
> Regads,
> Eduardo.
> Â
>
>
> ________________________________
> De: mark_ull <mores_p@...>
> Para: [email]
> Enviado: jueves, 21 de febrero de 2013 6:59
> Asunto: [ts2068] TS 2068 Video Problem
>
> Â
> Hello,
>
> I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
>
> Thanks,
> Mark
>
4. RE: [ts2068] Re: TS 2068 Video Problem
Rod H · Sat, 23 Feb 2013 17:10
If no one has replied...no problem pulling out keyboard cable. Goes back in easily as cable is quite stiff. Photos show generic ts2068 - nothing unusual.
To: [email]
From: [email]
Date: Sun, 24 Feb 2013 00:59:14 +0000
Subject: [ts2068] Re: TS 2068 Video Problem
I am posting pictures of the inside in case someone is interested.
https://www.dropbox.com/sh/wok7wqgcwhzjqip/HE7W0VoyE_
--- In [email], "mark_ull" wrote:
>
> Thanks Eduardo.
>
> I am opening up the machine. I see a flex cable connecting keyboard (top shell) to the main board. Is it safe to pull the cable out of the connector on the main board? It seems to fit in very tight to the connector.
>
>
> --- In [email], Eduardo Fuentes wrote:
> >
> > Hi Mark,
> > I think that the possible causes are:
> > Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
> > Faulty LM1889, it is located inside the modulator box.
> > Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
> > Regads,
> > Eduardo.
> > Â
> >
> >
> > ________________________________
> > De: mark_ull
> > Para: [email]
> > Enviado: jueves, 21 de febrero de 2013 6:59
> > Asunto: [ts2068] TS 2068 Video Problem
> >
> > Â
> > Hello,
> >
> > I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
> >
> > Thanks,
> > Mark
> >
>
5. Re: TS 2068 Video Problem
mark_ull · Sun, 24 Feb 2013 00:59
I am posting pictures of the inside in case someone is interested.
https://www.dropbox.com/sh/wok7wqgcwhzjqip/HE7W0VoyE_
--- In [email], "mark_ull" <mores_p@...> wrote:
>
> Thanks Eduardo.
>
> I am opening up the machine. I see a flex cable connecting keyboard (top shell) to the main board. Is it safe to pull the cable out of the connector on the main board? It seems to fit in very tight to the connector.
>
>
> --- In [email], Eduardo Fuentes <fuentesea@> wrote:
> >
> > Hi Mark,
> > I think that the possible causes are:
> > Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
> > Faulty LM1889, it is located inside the modulator box.
> > Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
> > Regads,
> > Eduardo.
> > Â
> >
> >
> > ________________________________
> > De: mark_ull <mores_p@>
> > Para: [email]
> > Enviado: jueves, 21 de febrero de 2013 6:59
> > Asunto: [ts2068] TS 2068 Video Problem
> >
> > Â
> > Hello,
> >
> > I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
> >
> > Thanks,
> > Mark
> >
>
6. RE: [ts2068] Re: TS 2068 Video Problem
Rod H · Sun, 24 Feb 2013 21:55
Hmmm... make sure you're pulling the right end and that your's isn't the one 2068 that had a soldered connector both ends.
Seriously: the ribbon connector might be corroded to the pcb connector and a little alcohol on a Q-tip might loosen it. A gentle pull back and forth on each side of the ribbon should ease it out. Force is not recommended.
To: [email]
From: [email]
Date: Mon, 25 Feb 2013 03:52:53 +0000
Subject: [ts2068] Re: TS 2068 Video Problem
Thanks Rod, the cable fits very tightly to its connector. I have a hard time pulling it out. I guess I fear too much about breaking cable. It will be several days before I can try again. When the time comes, I think I will just have to exert more force. Any tips would be welcome.
Mark
--- In [email], Rod H wrote:
>
> If no one has replied...no problem pulling out keyboard cable. Goes back in easily as cable is quite stiff. Photos show generic ts2068 - nothing unusual.
>
> To: [email]
> From: mores_p@...
> Date: Sun, 24 Feb 2013 00:59:14 +0000
> Subject: [ts2068] Re: TS 2068 Video Problem
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> I am posting pictures of the inside in case someone is interested.
>
>
>
> https://www.dropbox.com/sh/wok7wqgcwhzjqip/HE7W0VoyE_
>
>
>
> --- In [email], "mark_ull" wrote:
>
> >
>
> > Thanks Eduardo.
>
> >
>
> > I am opening up the machine. I see a flex cable connecting keyboard (top shell) to the main board. Is it safe to pull the cable out of the connector on the main board? It seems to fit in very tight to the connector.
>
> >
>
> >
>
> > --- In [email], Eduardo Fuentes wrote:
>
> > >
>
> > > Hi Mark,
>
> > > I think that the possible causes are:
>
> > > Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
>
> > > Faulty LM1889, it is located inside the modulator box.
>
> > > Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
>
> > > Regads,
>
> > > Eduardo.
>
> > > Â
>
> > >
>
> > >
>
> > > ________________________________
>
> > > De: mark_ull
>
> > > Para: [email]
>
> > > Enviado: jueves, 21 de febrero de 2013 6:59
>
> > > Asunto: [ts2068] TS 2068 Video Problem
>
> > >
>
> > > Â
>
> > > Hello,
>
> > >
>
> > > I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
>
> > >
>
> > > Thanks,
>
> > > Mark
>
> > >
>
> >
>
7. Re: TS 2068 Video Problem
mark_ull · Mon, 25 Feb 2013 03:52
Thanks Rod, the cable fits very tightly to its connector. I have a hard time pulling it out. I guess I fear too much about breaking cable. It will be several days before I can try again. When the time comes, I think I will just have to exert more force. Any tips would be welcome.
Mark
--- In [email], Rod H <rodh64@...> wrote:
>
> If no one has replied...no problem pulling out keyboard cable. Goes back in easily as cable is quite stiff. Photos show generic ts2068 - nothing unusual.
>
> To: [email]
> From: mores_p@...
> Date: Sun, 24 Feb 2013 00:59:14 +0000
> Subject: [ts2068] Re: TS 2068 Video Problem
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> I am posting pictures of the inside in case someone is interested.
>
>
>
> https://www.dropbox.com/sh/wok7wqgcwhzjqip/HE7W0VoyE_
>
>
>
> --- In [email], "mark_ull" wrote:
>
> >
>
> > Thanks Eduardo.
>
> >
>
> > I am opening up the machine. I see a flex cable connecting keyboard (top shell) to the main board. Is it safe to pull the cable out of the connector on the main board? It seems to fit in very tight to the connector.
>
> >
>
> >
>
> > --- In [email], Eduardo Fuentes wrote:
>
> > >
>
> > > Hi Mark,
>
> > > I think that the possible causes are:
>
> > > Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
>
> > > Faulty LM1889, it is located inside the modulator box.
>
> > > Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
>
> > > Regads,
>
> > > Eduardo.
>
> > > Â
>
> > >
>
> > >
>
> > > ________________________________
>
> > > De: mark_ull
>
> > > Para: [email]
>
> > > Enviado: jueves, 21 de febrero de 2013 6:59
>
> > > Asunto: [ts2068] TS 2068 Video Problem
>
> > >
>
> > > Â
>
> > > Hello,
>
> > >
>
> > > I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
>
> > >
>
> > > Thanks,
>
> > > Mark
>
> > >
>
> >
>
8. Re: TS 2068 Video Problem
mark_ull · Sun, 03 Mar 2013 06:22
Thanks for your suggestion, Rod.
I have successfully disconnected the keyboard cable from the mainboard. I didn't use alcohol though. Just gently pulled left-right a few times.
The next step is to follow Eduardo's suggestions for "no video" fixes. I will have my friend who knows enough about electronics check the possible faulty parts (UA78L12 and LM1889). Please feel free to provide suggestions.
Mark
--- In [email], Rod H <rodh64@...> wrote:
>
> Hmmm... make sure you're pulling the right end and that your's isn't the one 2068 that had a soldered connector both ends.
>
> Seriously: the ribbon connector might be corroded to the pcb connector and a little alcohol on a Q-tip might loosen it. A gentle pull back and forth on each side of the ribbon should ease it out. Force is not recommended.
>
9. Re: TS 2068 Video Problem
mark_ull · Sun, 03 Mar 2013 06:23
Forgot to mention that I have added a new photo showing the inside of the TV modulator.
https://www.dropbox.com/sh/wok7wqgcwhzjqip/HE7W0VoyE_
10. Re: [ts2068] TS 2068 Video Problem
Eduardo Fuentes · Tue, 5 Mar 2013 09:13:
Other cause may be faulty upper RAM (4416) chips. U12,U13,U17 and U18. U12/13 are 8000-BFFF memory addresses and U17/18 are C000-FFFF memory addresses.
Check RAM before than LM1889
To check RAM you can piggy back a known good ram chip to one of the suspected faulty chips. To do it turn off the computer first, piggy back the new chip and then turn on the computer. If the computer starts you found the culprit.
This method is not infalible and in some cases you have to replace the chip to test it, use sockets to facilitate future chip replacements.
________________________________
De: Eduardo Fuentes <[email]>
Para: "[email]" <[email]>
Enviado: viernes, 22 de febrero de 2013 17:18
Asunto: Re: [ts2068] TS 2068 Video Problem
Hi Mark,
I think that the possible causes are:
Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
Faulty LM1889, it is located inside the modulator box.
Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
Regads,
Eduardo.
________________________________
De: mark_ull <[email]>
Para: [email]
Enviado: jueves, 21 de febrero de 2013 6:59
Asunto: [ts2068] TS 2068 Video Problem
Hello,I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help. Thanks,Mark
11. Re: TS 2068 Video Problem
mark_ull · Sun, 10 Mar 2013 00:37
Thanks for the info, Eduardo.
--- In [email], Eduardo Fuentes <fuentesea@...> wrote:
>
> Other cause may be faulty upper RAM (4416) chips. U12,U13,U17 and U18. U12/13 are 8000-BFFF memory addresses and U17/18 are C000-FFFF memory addresses.
> Check RAM before than LM1889
> To check RAM you can piggy back a known good ram chip to one of the suspected faulty chips. To do it turn off the computer first, piggy back the new chip and then turn on the computer. If the computer starts you found the culprit.
> This method is not infalible and in some cases you have to replace the chip to test it, use sockets to facilitate future chip replacements.
>
>
> ________________________________
> De: Eduardo Fuentes <fuentesea@...>
> Para: "[email]" <[email]>
> Enviado: viernes, 22 de febrero de 2013 17:18
> Asunto: Re: [ts2068] TS 2068 Video Problem
>
> Â
> Hi Mark,
> I think that the possible causes are:
> Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
> Faulty LM1889, it is located inside the modulator box.
> Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
> Regads,
> Eduardo.
> Â
>
>
> ________________________________
> De: mark_ull <mores_p@...>
> Para: [email]
> Enviado: jueves, 21 de febrero de 2013 6:59
> Asunto: [ts2068] TS 2068 Video Problem
>
> Â
> Hello,I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help. Thanks,Mark
>
12. Re: TS 2068 Video Problem
unbonnevie · Sat, 27 Apr 2013 15:36
Hi,
Just joined this group and just bought a TS2068, which has the same exact problem like yours. Have you had success of fixing yours?
Thanks for sharing any info.
--- In [email], "mark_ull" <mores_p@...> wrote:
>
> Thanks for the info, Eduardo.
>
>
>
> --- In [email], Eduardo Fuentes <fuentesea@> wrote:
> >
> > Other cause may be faulty upper RAM (4416) chips. U12,U13,U17 and U18. U12/13 are 8000-BFFF memory addresses and U17/18 are C000-FFFF memory addresses.
> > Check RAM before than LM1889
> > To check RAM you can piggy back a known good ram chip to one of the suspected faulty chips. To do it turn off the computer first, piggy back the new chip and then turn on the computer. If the computer starts you found the culprit.
> > This method is not infalible and in some cases you have to replace the chip to test it, use sockets to facilitate future chip replacements.
> >
> >
> > ________________________________
> > De: Eduardo Fuentes <fuentesea@>
> > Para: "[email]" <[email]>
> > Enviado: viernes, 22 de febrero de 2013 17:18
> > Asunto: Re: [ts2068] TS 2068 Video Problem
> >
> > Â
> > Hi Mark,
> > I think that the possible causes are:
> > Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
> > Faulty LM1889, it is located inside the modulator box.
> > Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
> > Regads,
> > Eduardo.
> > Â
> >
> >
> > ________________________________
> > De: mark_ull <mores_p@>
> > Para: [email]
> > Enviado: jueves, 21 de febrero de 2013 6:59
> > Asunto: [ts2068] TS 2068 Video Problem
> >
> > Â
> > Hello,I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help. Thanks,Mark
> >
>
13. Re: TS 2068 Video Problem
unbonnevie · Sat, 27 Apr 2013 22:45
--- In [email], Eduardo Fuentes <fuentesea@...> wrote:
>
> Hi Mark,
> I think that the possible causes are:
> Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
The above can be tested with a multimeter by checking the voltages on the 12V/5V+ pins of the edge connectors of the expansion port.
> Faulty LM1889, it is located inside the modulator box.
I think an oscilloscope can help here before pulling things out.
Datasheet http://rbsfm.org/Downloads/Datasheet/LM/LM1889.PDF
Probably look at PIN 11 & 10, channel B & A output, respectively.
> Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
> Regads,
> Eduardo.
You also mentioned possibly bad DRAM chips. Oscilloscope should help. POKEing or PEEKING into memory locations that you mentioned to see if any square waves shown on the scope.
> Â
>
>
> ________________________________
> De: mark_ull <mores_p@...>
> Para: [email]
> Enviado: jueves, 21 de febrero de 2013 6:59
> Asunto: [ts2068] TS 2068 Video Problem
>
> Â
> Hello,
>
> I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
>
> Thanks,
> Mark
>
14. Re: TS 2068 Video Problem
unbonnevie · Sun, 28 Apr 2013 04:28
--- In [email], "unbonnevie" <unbonnevie@...> wrote:
>
>
>
> --- In [email], Eduardo Fuentes <fuentesea@> wrote:
> >
> > Hi Mark,
> > I think that the possible causes are:
> > Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
>
> The above can be tested with a multimeter by checking the voltages on the 12V/5V+ pins of the edge connectors of the expansion port.
Here is what I found with my testing for the above. Looking at the expansion port directly AND from left to right. First BOTTOM pin is GND, 3rd BOTTOM pin is +15V, and 4th BOTTOM pin is +5V.
I have TWO TS2068s. The working one shows me a 4.97V for the supposedly 5V. And shows me 19.34V for the supposedly +15V. Wow! That's high.
The one with no video output shows me a 5.23V for the supposedly 5V. And shows me also 19.34V for the supposedly +15V.
Why 19.34V but not within proximity of +15V?
I use a very reliable Fluke multimeter.
Thoughts anyone? Could someone please try out on their working TS2068?
>
> > Faulty LM1889, it is located inside the modulator box.
>
> I think an oscilloscope can help here before pulling things out.
>
> Datasheet http://rbsfm.org/Downloads/Datasheet/LM/LM1889.PDF
>
> Probably look at PIN 11 & 10, channel B & A output, respectively.
>
> > Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
> > Regads,
> > Eduardo.
>
> You also mentioned possibly bad DRAM chips. Oscilloscope should help. POKEing or PEEKING into memory locations that you mentioned to see if any square waves shown on the scope.
>
> > Â
> >
> >
> > ________________________________
> > De: mark_ull <mores_p@>
> > Para: [email]
> > Enviado: jueves, 21 de febrero de 2013 6:59
> > Asunto: [ts2068] TS 2068 Video Problem
> >
> > Â
> > Hello,
> >
> > I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
> >
> > Thanks,
> > Mark
> >
>
15. Re: TS 2068 Video Problem
unbonnevie · Sun, 28 Apr 2013 04:48
--- In [email], "unbonnevie" <unbonnevie@...> wrote:
>
>
>
> --- In [email], "unbonnevie" <unbonnevie@> wrote:
> >
> >
> >
> > --- In [email], Eduardo Fuentes <fuentesea@> wrote:
> > >
> > > Hi Mark,
> > > I think that the possible causes are:
> > > Faulty UA78L12 voltage regulator, it is located near the video modulator and it is like a transistor.
> >
> > The above can be tested with a multimeter by checking the voltages on the 12V/5V+ pins of the edge connectors of the expansion port.
>
> Here is what I found with my testing for the above. Looking at the expansion port directly AND from left to right. First BOTTOM pin is GND, 3rd BOTTOM pin is +15V, and 4th BOTTOM pin is +5V.
>
The above should read "AND from RIGHT to LEFT" Sorry...
> I have TWO TS2068s. The working one shows me a 4.97V for the supposedly 5V. And shows me 19.34V for the supposedly +15V. Wow! That's high.
>
> The one with no video output shows me a 5.23V for the supposedly 5V. And shows me also 19.34V for the supposedly +15V.
>
> Why 19.34V but not within proximity of +15V?
>
> I use a very reliable Fluke multimeter.
>
> Thoughts anyone? Could someone please try out on their working TS2068?
> >
> > > Faulty LM1889, it is located inside the modulator box.
> >
> > I think an oscilloscope can help here before pulling things out.
> >
> > Datasheet http://rbsfm.org/Downloads/Datasheet/LM/LM1889.PDF
> >
> > Probably look at PIN 11 & 10, channel B & A output, respectively.
> >
> > > Both fixes imply component replacement, no too difficult if you have some experience with the solder iron.
> > > Regads,
> > > Eduardo.
> >
> > You also mentioned possibly bad DRAM chips. Oscilloscope should help. POKEing or PEEKING into memory locations that you mentioned to see if any square waves shown on the scope.
> >
> > > Â
> > >
> > >
> > > ________________________________
> > > De: mark_ull <mores_p@>
> > > Para: [email]
> > > Enviado: jueves, 21 de febrero de 2013 6:59
> > > Asunto: [ts2068] TS 2068 Video Problem
> > >
> > > Â
> > > Hello,
> > >
> > > I have a TS 2068 showing "no video" (black screen) from both composite and rf outputs. The machine appears functional as I typed in a short BASIC program to play a BEEP sound and it worked. Any advices for possible fixes? I am not a hardware guy. But if the fix is not too complicated, I can probably ask my friend to help.
> > >
> > > Thanks,
> > > Mark
> > >
> >
>
Indexed under
TS2068 / TC2068 · Video upgrades (composite, RGB, HDMI) · Repair & restoration