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Hi all,

My mount is fixed permanently to a pier and I've used a good pointing model for some time. A couple of weeks ago Gemini (on MI-250) started up without giving me the option to warm start or warm re-start. I did a re-alignment and continued. All settings appeared to be ok, time, mount type, location etc. Since then, this situation has re-occurred every time that I've powered-up. The mount is about 5 years old (rocker power switch version) and so I thought that the battery might need replacing. Battery replaced (CR2354, not CR2032 as detailed in manual), but the 'cold start only' problem remains.
Each time, there are no indications of malfunction, just four initial dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy




------------------------------------

Yahoo! Groups Links

Are you using Gemini driver or the hand paddle?

Jim

tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing model for some time. A couple of weeks ago Gemini (on MI-250) started up without giving me the option to warm start or warm re-start. I did a re-alignment and continued. All settings appeared to be ok, time, mount type, location etc. Since then, this situation has re-occurred every time that I've powered-up. The mount is about 5 years old (rocker power switch version) and so I thought that the battery might need replacing. Battery replaced (CR2354, not CR2032 as detailed in manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy




------------------------------------

Yahoo! Groups Links

Are you using Gemini driver or the hand paddle?

Jim

tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing model for some time. A couple of weeks ago Gemini (on MI-250) started up without giving me the option to warm start or warm re-start. I did a re-alignment and continued. All settings appeared to be ok, time, mount type, location etc. Since then, this situation has re-occurred every time that I've powered-up. The mount is about 5 years old (rocker power switch version) and so I thought that the battery might need replacing. Battery replaced (CR2354, not CR2032 as detailed in manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy




------------------------------------

Yahoo! Groups Links

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

Hi Tom,

yes, I have the latest Gemini I PCB with the led lighted rocker switch. I noted the origianl battery polarity before removing it and ensured that the replacement was fitted in exactly the same way. The battery should not be the cause of the problem, but maybe I've fitted a dud.

Any more ideas?

Regards,

Andy

--- In Gemini_Users@..., "tom@" <tom@> wrote:

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

Andy,

further developments this evening...

Now at power-up the HC just displays a single dot and then goes blank.

Anyone know the meaning of the diagnostic dots at Gemini start-up?

Yes ;-)

I was thinking about what you described and suspected the voltage
supervisor Q3. It is a MCP809-450. This new development assures me about
that.

The voltage supervisor has the important task to shut down Gemini in
case of a power loss. If it doesn't work, coordinates and time at
shutdown are not saved, meaning that only a Cold Start remains possible.

It has the second task to check if the internal +5V voltage has
established at startup. As long as the main processor is waiting for its
power good signal, only the one dot is displayed. If it stays forever,
either the voltage does not reach the nominal value or Q3 is defective.
With your description I suppose the latter.

Ren???

TIA,

Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@...> wrote:

Hi Tom,

yes, I have the latest Gemini I PCB with the led lighted rocker switch. I noted the origianl battery polarity before removing it and ensured that the replacement was fitted in exactly the same way. The battery should not be the cause of the problem, but maybe I've fitted a dud.

Any more ideas?

Regards,

Andy

--- In Gemini_Users@..., "tom@"<tom@> wrote:

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

Make that U3, not Q3.

搁别苍é

Rene Goerlich schrieb:

Andy,

further developments this evening...

Now at power-up the HC just displays a single dot and then goes blank.

Anyone know the meaning of the diagnostic dots at Gemini start-up?

Yes ;-)

I was thinking about what you described and suspected the voltage
supervisor Q3. It is a MCP809-450. This new development assures me about
that.

The voltage supervisor has the important task to shut down Gemini in
case of a power loss. If it doesn't work, coordinates and time at
shutdown are not saved, meaning that only a Cold Start remains possible.

It has the second task to check if the internal +5V voltage has
established at startup. As long as the main processor is waiting for its
power good signal, only the one dot is displayed. If it stays forever,
either the voltage does not reach the nominal value or Q3 is defective.
With your description I suppose the latter.

搁别苍é

TIA,

Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi Tom,

yes, I have the latest Gemini I PCB with the led lighted rocker switch. I noted the origianl battery polarity before removing it and ensured that the replacement was fitted in exactly the same way. The battery should not be the cause of the problem, but maybe I've fitted a dud.

Any more ideas?

Regards,

Andy

--- In Gemini_Users@..., "tom@"<tom@> wrote:

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

[Non-text portions of this message have been removed]

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

Hi Andy,

is this chip an easy replacement? can it be done by the end-user? Where can the chip be obtained in the UK?

Very easy. It is a standard chip, only three pins, every good
electronics shop should have it and should be able to replace it on the
board.

Thanks very much for the feedback.

You're very welcome.

Regards,
搁别苍é

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Make that U3, not Q3.

搁别苍é

Rene Goerlich schrieb:

Andy,

further developments this evening...

Now at power-up the HC just displays a single dot and then goes blank.

Anyone know the meaning of the diagnostic dots at Gemini start-up?

Yes ;-)

I was thinking about what you described and suspected the voltage
supervisor Q3. It is a MCP809-450. This new development assures me about
that.

The voltage supervisor has the important task to shut down Gemini in
case of a power loss. If it doesn't work, coordinates and time at
shutdown are not saved, meaning that only a Cold Start remains possible.

It has the second task to check if the internal +5V voltage has
established at startup. As long as the main processor is waiting for its
power good signal, only the one dot is displayed. If it stays forever,
either the voltage does not reach the nominal value or Q3 is defective.
With your description I suppose the latter.

搁别苍é

TIA,

Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi Tom,

yes, I have the latest Gemini I PCB with the led lighted rocker switch. I noted the origianl battery polarity before removing it and ensured that the replacement was fitted in exactly the same way. The battery should not be the cause of the problem, but maybe I've fitted a dud.

Any more ideas?

Regards,

Andy

--- In Gemini_Users@..., "tom@"<tom@> wrote:

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

Hi 搁别苍é,

I've checked ny PCB but can't locate component U3.

Looking at the datasheet for the MCP809-450, I thought that you may mean D3? There are 4 similar devices labelled D1, D2, D3, D4.

Please can you confirm the location of U3.

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich <Rene@> wrote:

Hi Andy,

is this chip an easy replacement? can it be done by the end-user? Where can the chip be obtained in the UK?

Very easy. It is a standard chip, only three pins, every good
electronics shop should have it and should be able to replace it on the
board.

Thanks very much for the feedback.

You're very welcome.

Regards,
搁别苍é

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Make that U3, not Q3.

搁别苍é

Rene Goerlich schrieb:

Andy,

further developments this evening...

Now at power-up the HC just displays a single dot and then goes blank.

Anyone know the meaning of the diagnostic dots at Gemini start-up?

Yes ;-)

I was thinking about what you described and suspected the voltage
supervisor Q3. It is a MCP809-450. This new development assures me about
that.

The voltage supervisor has the important task to shut down Gemini in
case of a power loss. If it doesn't work, coordinates and time at
shutdown are not saved, meaning that only a Cold Start remains possible.

It has the second task to check if the internal +5V voltage has
established at startup. As long as the main processor is waiting for its
power good signal, only the one dot is displayed. If it stays forever,
either the voltage does not reach the nominal value or Q3 is defective.
With your description I suppose the latter.

搁别苍é

TIA,

Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi Tom,

yes, I have the latest Gemini I PCB with the led lighted rocker switch. I noted the origianl battery polarity before removing it and ensured that the replacement was fitted in exactly the same way. The battery should not be the cause of the problem, but maybe I've fitted a dud.

Any more ideas?

Regards,

Andy

--- In Gemini_Users@..., "tom@"<tom@> wrote:

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

[Non-text portions of this message have been removed]

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

Hi Andy,

managed to locate U3 with better lighting!

OK, with the unit powered, I've measured 5V between both Vdd to Vss and Vdd to RST. Is this normal and does it agree with your fault diagnosis?

Do you like to ask questions the complicated way? ;-)

Short answer: yes.

I propose to use Vss/GND as common zero potential. Vdd or Vcc = 5V is
fine if measured against Vss/GND, what we can assume here.
I interpret 5V from Vss/Vdd to /RST as /RST to be at 0V. This is not
normal, indicates that /RST is still active although Vss is above 4.5V,
showing that U3 lifted itsself into Nirwana.

Thanks again for your help.

Happy soldering ;-)

Best,
Ren???

Regards,
Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@...> wrote:

Hi Ren???,

I've checked ny PCB but can't locate component U3.

Looking at the datasheet for the MCP809-450, I thought that you may mean D3? There are 4 similar devices labelled D1, D2, D3, D4.

Please can you confirm the location of U3.

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Hi Andy,

is this chip an easy replacement? can it be done by the end-user? Where can the chip be obtained in the UK?

Very easy. It is a standard chip, only three pins, every good
electronics shop should have it and should be able to replace it on the
board.

Thanks very much for the feedback.

You're very welcome.

Regards,
Ren???

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Make that U3, not Q3.

Ren???

Rene Goerlich schrieb:

Andy,

further developments this evening...

Now at power-up the HC just displays a single dot and then goes blank.

Anyone know the meaning of the diagnostic dots at Gemini start-up?

Yes ;-)

I was thinking about what you described and suspected the voltage
supervisor Q3. It is a MCP809-450. This new development assures me about
that.

The voltage supervisor has the important task to shut down Gemini in
case of a power loss. If it doesn't work, coordinates and time at
shutdown are not saved, meaning that only a Cold Start remains possible.

It has the second task to check if the internal +5V voltage has
established at startup. As long as the main processor is waiting for its
power good signal, only the one dot is displayed. If it stays forever,
either the voltage does not reach the nominal value or Q3 is defective.
With your description I suppose the latter.

Ren???

TIA,

Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi Tom,

yes, I have the latest Gemini I PCB with the led lighted rocker switch. I noted the origianl battery polarity before removing it and ensured that the replacement was fitted in exactly the same way. The battery should not be the cause of the problem, but maybe I've fitted a dud.

Any more ideas?

Regards,

Andy

--- In Gemini_Users@..., "tom@"<tom@> wrote:

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

Andy,

I intended to write ...Vcc/Vdd to /RST ...

搁别苍é


Rene Goerlich schrieb:

Hi Andy,

managed to locate U3 with better lighting!

OK, with the unit powered, I've measured 5V between both Vdd to Vss and Vdd to RST. Is this normal and does it agree with your fault diagnosis?

Do you like to ask questions the complicated way? ;-)

Short answer: yes.

I propose to use Vss/GND as common zero potential. Vdd or Vcc = 5V is
fine if measured against Vss/GND, what we can assume here.
I interpret 5V from Vss/Vdd to /RST as /RST to be at 0V. This is not
normal, indicates that /RST is still active although Vss is above 4.5V,
showing that U3 lifted itsself into Nirwana.

Thanks again for your help.

Happy soldering ;-)

Best,
搁别苍é

Regards,
Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi 搁别苍é,

I've checked ny PCB but can't locate component U3.

Looking at the datasheet for the MCP809-450, I thought that you may mean D3? There are 4 similar devices labelled D1, D2, D3, D4.

Please can you confirm the location of U3.

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Hi Andy,

is this chip an easy replacement? can it be done by the end-user? Where can the chip be obtained in the UK?

Very easy. It is a standard chip, only three pins, every good
electronics shop should have it and should be able to replace it on the
board.

Thanks very much for the feedback.

You're very welcome.

Regards,
搁别苍é

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Make that U3, not Q3.

搁别苍é

Rene Goerlich schrieb:

Andy,

further developments this evening...

Now at power-up the HC just displays a single dot and then goes blank.

Anyone know the meaning of the diagnostic dots at Gemini start-up?

Yes ;-)

I was thinking about what you described and suspected the voltage
supervisor Q3. It is a MCP809-450. This new development assures me about
that.

The voltage supervisor has the important task to shut down Gemini in
case of a power loss. If it doesn't work, coordinates and time at
shutdown are not saved, meaning that only a Cold Start remains possible.

It has the second task to check if the internal +5V voltage has
established at startup. As long as the main processor is waiting for its
power good signal, only the one dot is displayed. If it stays forever,
either the voltage does not reach the nominal value or Q3 is defective.
With your description I suppose the latter.

搁别苍é

TIA,

Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi Tom,

yes, I have the latest Gemini I PCB with the led lighted rocker switch. I noted the origianl battery polarity before removing it and ensured that the replacement was fitted in exactly the same way. The battery should not be the cause of the problem, but maybe I've fitted a dud.

Any more ideas?

Regards,

Andy

--- In Gemini_Users@..., "tom@"<tom@> wrote:

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

[Non-text portions of this message have been removed]

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

------------------------------------

Yahoo! Groups Links

Hi Andy,

thanks for the advice to replace the supervisor chip. This has now been done and the battery removed for 30mins. There has been progress but now on power-up the HC gives the messages:

SRAM failure
WD reset

The menu system is available but some of the sub-menus are corrupted, e.g. some of the mount type options are random meaningless characters, as are items from the star database.

oh yes, there are random beeps emitted with going through the menu system. The HC will not drive the motors when selected.

So, again, please could you offer a diagnosis for the above?

Many thanks for your continuing support!

I'm not sure if your new chip works correctly. It has to prevent the
main chip from accessing the SRAM until the voltage has reached the
required 4.5 volts.

What you can check: did you replace the CR battery correctly (not
bending the minus pole to the bottom). You can also try without the battery.
Also, check all the RTC settings (date/time/alarm time) and replace
garbled characters there. RTC and SRAM chip share a data bus.

Does switching power off/on quickly change things?

Ren???

Regards,

Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@...> wrote:

Andy,

I intended to write ...Vcc/Vdd to /RST ...

Ren???


Rene Goerlich schrieb:

Hi Andy,

managed to locate U3 with better lighting!

OK, with the unit powered, I've measured 5V between both Vdd to Vss and Vdd to RST. Is this normal and does it agree with your fault diagnosis?

Do you like to ask questions the complicated way? ;-)

Short answer: yes.

I propose to use Vss/GND as common zero potential. Vdd or Vcc = 5V is
fine if measured against Vss/GND, what we can assume here.
I interpret 5V from Vss/Vdd to /RST as /RST to be at 0V. This is not
normal, indicates that /RST is still active although Vss is above 4.5V,
showing that U3 lifted itsself into Nirwana.

Thanks again for your help.

Happy soldering ;-)

Best,
Ren???

Regards,
Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi Ren???,

I've checked ny PCB but can't locate component U3.

Looking at the datasheet for the MCP809-450, I thought that you may mean D3? There are 4 similar devices labelled D1, D2, D3, D4.

Please can you confirm the location of U3.

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Hi Andy,

is this chip an easy replacement? can it be done by the end-user? Where can the chip be obtained in the UK?

Very easy. It is a standard chip, only three pins, every good
electronics shop should have it and should be able to replace it on the
board.

Thanks very much for the feedback.

You're very welcome.

Regards,
Ren???

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Make that U3, not Q3.

Ren???

Rene Goerlich schrieb:

Andy,

further developments this evening...

Now at power-up the HC just displays a single dot and then goes blank.

Anyone know the meaning of the diagnostic dots at Gemini start-up?

Yes ;-)

I was thinking about what you described and suspected the voltage
supervisor Q3. It is a MCP809-450. This new development assures me about
that.

The voltage supervisor has the important task to shut down Gemini in
case of a power loss. If it doesn't work, coordinates and time at
shutdown are not saved, meaning that only a Cold Start remains possible.

It has the second task to check if the internal +5V voltage has
established at startup. As long as the main processor is waiting for its
power good signal, only the one dot is displayed. If it stays forever,
either the voltage does not reach the nominal value or Q3 is defective.
With your description I suppose the latter.

Ren???

TIA,

Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi Tom,

yes, I have the latest Gemini I PCB with the led lighted rocker switch. I noted the origianl battery polarity before removing it and ensured that the replacement was fitted in exactly the same way. The battery should not be the cause of the problem, but maybe I've fitted a dud.

Any more ideas?

Regards,

Andy

--- In Gemini_Users@..., "tom@"<tom@> wrote:

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy

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oops, I meant the 2 little _plus_ connectors to the CR2032 battery.

Rene Goerlich schrieb:

Hi Andy,

thanks for the advice to replace the supervisor chip. This has now been done and the battery removed for 30mins. There has been progress but now on power-up the HC gives the messages:

SRAM failure
WD reset

The menu system is available but some of the sub-menus are corrupted, e.g. some of the mount type options are random meaningless characters, as are items from the star database.

oh yes, there are random beeps emitted with going through the menu system. The HC will not drive the motors when selected.

So, again, please could you offer a diagnosis for the above?

Many thanks for your continuing support!

I'm not sure if your new chip works correctly. It has to prevent the
main chip from accessing the SRAM until the voltage has reached the
required 4.5 volts.

What you can check: did you replace the CR battery correctly (not
bending the minus pole to the bottom). You can also try without the battery.
Also, check all the RTC settings (date/time/alarm time) and replace
garbled characters there. RTC and SRAM chip share a data bus.

Does switching power off/on quickly change things?

搁别苍é

Regards,

Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Andy,

I intended to write ...Vcc/Vdd to /RST ...

搁别苍é


Rene Goerlich schrieb:

Hi Andy,

managed to locate U3 with better lighting!

OK, with the unit powered, I've measured 5V between both Vdd to Vss and Vdd to RST. Is this normal and does it agree with your fault diagnosis?

Do you like to ask questions the complicated way? ;-)

Short answer: yes.

I propose to use Vss/GND as common zero potential. Vdd or Vcc = 5V is
fine if measured against Vss/GND, what we can assume here.
I interpret 5V from Vss/Vdd to /RST as /RST to be at 0V. This is not
normal, indicates that /RST is still active although Vss is above 4.5V,
showing that U3 lifted itsself into Nirwana.

Thanks again for your help.

Happy soldering ;-)

Best,
搁别苍é

Regards,
Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi 搁别苍é,

I've checked ny PCB but can't locate component U3.

Looking at the datasheet for the MCP809-450, I thought that you may mean D3? There are 4 similar devices labelled D1, D2, D3, D4.

Please can you confirm the location of U3.

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Hi Andy,

is this chip an easy replacement? can it be done by the end-user? Where can the chip be obtained in the UK?

Very easy. It is a standard chip, only three pins, every good
electronics shop should have it and should be able to replace it on the
board.

Thanks very much for the feedback.

You're very welcome.

Regards,
搁别苍é

Regards,
Andy

--- In Gemini_Users@..., Rene Goerlich<Rene@> wrote:

Make that U3, not Q3.

搁别苍é

Rene Goerlich schrieb:

Andy,

further developments this evening...

Now at power-up the HC just displays a single dot and then goes blank.

Anyone know the meaning of the diagnostic dots at Gemini start-up?

Yes ;-)

I was thinking about what you described and suspected the voltage
supervisor Q3. It is a MCP809-450. This new development assures me about
that.

The voltage supervisor has the important task to shut down Gemini in
case of a power loss. If it doesn't work, coordinates and time at
shutdown are not saved, meaning that only a Cold Start remains possible.

It has the second task to check if the internal +5V voltage has
established at startup. As long as the main processor is waiting for its
power good signal, only the one dot is displayed. If it stays forever,
either the voltage does not reach the nominal value or Q3 is defective.
With your description I suppose the latter.

搁别苍é

TIA,

Andy

--- In Gemini_Users@..., "tillyscope"<andy.wellington99@> wrote:

Hi Tom,

yes, I have the latest Gemini I PCB with the led lighted rocker switch. I noted the origianl battery polarity before removing it and ensured that the replacement was fitted in exactly the same way. The battery should not be the cause of the problem, but maybe I've fitted a dud.

Any more ideas?

Regards,

Andy

--- In Gemini_Users@..., "tom@"<tom@> wrote:

Andy
Please make sure you installed the battery correctly. The battery needs
to have the + sign visible (up) when installed. I am assuming that
your Gemini has a red lighted Rocker switch for power since you used a
CR2354 battery.


If your battery holder looks like this then the battery needs to be a
CR2032. The Gemini units with this battery normally has slide power
switches.


Tom Hilton

On 3/4/2011 12:20 PM, tillyscope wrote:

Hi all,

My mount is fixed permanently to a pier and I've used a good pointing
model for some time. A couple of weeks ago Gemini (on MI-250) started
up without giving me the option to warm start or warm re-start. I did
a re-alignment and continued. All settings appeared to be ok, time,
mount type, location etc. Since then, this situation has re-occurred
every time that I've powered-up. The mount is about 5 years old
(rocker power switch version) and so I thought that the battery might
need replacing. Battery replaced (CR2354, not CR2032 as detailed in
manual), but the 'cold start only' problem remains.

Each time, there are no indications of malfunction, just four initial
dots at start-up, followed by the usual cold start sequence.

I would be very grateful if you provide any advice.

Best regards,

Andy