TS1000 with no image :_(
Re: TS1000 with no image :_(
Did the static test.
Without the ULA, Z80 pin 6 is high at 5.4v
With the wire from ULA socket pin 14 to pin 40, Z80 pin 6 is low at 0.13v..
So Tr2 is good..
I wonder why ULA pin 14 gave me such a low tension..?
May be tomorrow I can get access to an oscilloscope..
What should I look for?
Perhaps the picture helps someone in the future..
Just for the curiosity, why does it has to be a solid core wire?
Thanks again!!
Without the ULA, Z80 pin 6 is high at 5.4v
With the wire from ULA socket pin 14 to pin 40, Z80 pin 6 is low at 0.13v..
So Tr2 is good..
I wonder why ULA pin 14 gave me such a low tension..?
May be tomorrow I can get access to an oscilloscope..
What should I look for?
Perhaps the picture helps someone in the future..
Just for the curiosity, why does it has to be a solid core wire?
Thanks again!!
Re: TS1000 with no image :_(
Because multi Filament wires don't go into the holes of a Socket.
And if you put solder on them they might already be too thick to fit into.
And even more critical: These tinned wires tend to break off where the Solder stops making it near to impossible to get the rest out of the socket.
Kind regards
Paul
In theory, there is no difference between theory and practice. But, in practice, there is.
Re: TS1000 with no image :_(
It's been a while since last post but now with some free time it looks Like I found something.
Just to remember.:
Issue 3 Timex Sinclair boars with no cursor.
RAM, ULA, Z80, CLK inv circuit and TR2 Checked OK.
ULA pin 14 has a low 0.1v so went back to ULA pin 35 in direction to the resonator and found this Yellowish resistor with a black substance to its leads.. I can't measure any current thru it.. (open circuit) I couldn't find an issue 3 board layout but it looks like marked as C6 ( ) in issue 1 that is a 100uF capacitor.. but this doesn't looks like one. I ve seen several boards pictures on the net and It looks like there are many variations in components in this board region..
Anyway.. can any one confirm me the value of this resistor if it is one??
And
How can I check if the resonator is OK?
Thanks
Just to remember.:
Issue 3 Timex Sinclair boars with no cursor.
RAM, ULA, Z80, CLK inv circuit and TR2 Checked OK.
ULA pin 14 has a low 0.1v so went back to ULA pin 35 in direction to the resonator and found this Yellowish resistor with a black substance to its leads.. I can't measure any current thru it.. (open circuit) I couldn't find an issue 3 board layout but it looks like marked as C6 ( ) in issue 1 that is a 100uF capacitor.. but this doesn't looks like one. I ve seen several boards pictures on the net and It looks like there are many variations in components in this board region..
Anyway.. can any one confirm me the value of this resistor if it is one??
And
How can I check if the resonator is OK?
Thanks
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
Re: TS1000 with no image :_(
It's a capacitor. The black stuff doesn't look encouraging though, but it may still be ok. Does your multimeter have capacitance test mode? Replace it with a modern ceramic one if you have one.
I'm Chris, a Brit in Germany (Chr$ on the QL forum). https:\\QXL.WIN < QL related collection.
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Re: TS1000 with no image :_(
It looks to me like a 10.1Ohm resistor in a 100pF capacitor socket. This cap happens to be the connection between the 6.5MHz crystal and the ULA input, so you don't have a clock in the system. This should be replaced by a 100pF cap. Here is the schematic:bola_dor wrote: ↑Mon May 04, 2020 7:26 am It's been a while since last post but now with some free time it looks Like I found something.
Just to remember.:
Issue 3 Timex Sinclair boars with no cursor.
RAM, ULA, Z80, CLK inv circuit and TR2 Checked OK.
ULA pin 14 has a low 0.1v so went back to ULA pin 35 in direction to the resonator and found this Yellowish resistor with a black substance to its leads.. I can't measure any current thru it.. (open circuit)20200504_000615.jpg
I couldn't find an issue 3 board layout but it looks like marked as C6 ( ) in issue 1 that is a 100uF capacitor.. but this doesn't looks like one. I ve seen several boards pictures on the net and It looks like there are many variations in components in this board region..
Anyway.. can any one confirm me the value of this resistor if it is one??
And
How can I check if the resonator is OK?
Thanks
John
Re: TS1000 with no image :_(
I've learned now that some caps looks like that.. https://en.m.wikipedia.org/wiki/Electro ... or-coding my other ISSUE 3 TIMEX /Portugal board is exactly like this,It looks to me like a 10.1Ohm resistor in a 100pF capacitor socket. This cap happens to be the connection between the 6.5MHz crystal and the ULA input, so you don't have a clock in the system. This should be replaced by a 100pF cap. Here is the schematic:
schema_ZX81_Fr_zoom.jpg
So it's a 100pF capacitor..
Should one of this do the work? Thanks
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
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Re: TS1000 with no image :_(
Yes (hope the crystal is still okay). If you did find a scope, you can verify an appropriate clock signal by probing pin 6 on the Z80.bola_dor wrote: ↑Mon May 04, 2020 10:13 pm I've learned now that some caps looks like that.. https://en.m.wikipedia.org/wiki/Electro ... or-coding my other ISSUE 3 TIMEX /Portugal board is exactly like this,
So it's a 100pF capacitor..
Should one of this do the work?capacitor-ceramico-100pf-101-.jpg
Thanks
John
Re: TS1000 with no image :_(
Yes, but whether that sorts your problem is another matter!
I'm Chris, a Brit in Germany (Chr$ on the QL forum). https:\\QXL.WIN < QL related collection.
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Re: TS1000 with no image :_(
Erm, I stand corrected. I just checked my ZX81 and it has the same component. I've never seen a cap that looked to resistor-y. In any case, if you measure the impedance across this cap it should be off the scale, maybe not right away, but after a few seconds with the probes in place. If it is low, you know the cap is bad. I just measured mine on my working board.
John
Re: TS1000 with no image :_(
There are several of these Yellowish resistor like capacitors in my board.. and other two of them have black legs.. but I don't have any spares now.. I am going to check is I am just Lucky now with C6 replaced with a new ceramic one..stroebeljc wrote: ↑Tue May 05, 2020 12:59 amErm, I stand corrected. I just checked my ZX81 and it has the same component. I've never seen a cap that looked to resistor-y. In any case, if you measure the impedance across this cap it should be off the scale, maybe not right away, but after a few seconds with the probes in place. If it is low, you know the cap is bad. I just measured mine on my working board.
I don't have an oscilloscope nor a logic probe by now but Z80 pin 6 measured near 5v. So it were not pulsing or pulsing too high... ULA 14 were to low.. so I went Into the resonator.. an found that black legs..
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come