CTC chassis eeprom question

[Bill]

Hello all- I have a CTC187 chassis that is completely dead. voltages
on the STK regulator are perfect. Pin 8 of the eeprom has 5v. However,
pins 5 and 6 have only 3 and 2.7 volts respectively, even with the
eeprom removed. Could this possibly be my problem ? I believe those
pins should be around 5 volts each. If so, does anyone know what can
cause the voltage here to go low ? I hate to replace the micro unless
I'm certain it is the problem. Thanks.

 

[john]

Bill Does the set chirp when you plug it in ?

If not check that resistor off the Big Filter cap
its a little 1/8 watt 1.2 m or something.

kip

--
"Watch the return E-Mail addy its false"
"Bill" <elect21st@aol.com> wrote in message
news:8fb59540.0404090313.4cb68588@posting.google.com...

Hello all- I have a CTC187 chassis that is completely dead. voltages
on the STK regulator are perfect. Pin 8 of the eeprom has 5v. However,
pins 5 and 6 have only 3 and 2.7 volts respectively, even with the
eeprom removed. Could this possibly be my problem ? I believe those
pins should be around 5 volts each. If so, does anyone know what can
cause the voltage here to go low ? I hate to replace the micro unless
I'm certain it is the problem. Thanks.

 

[Bill]

"john" <va3mmTAKEOUTTHIS@niagara.com> wrote in message news:<newscache$4wowvh$aca$1@newsfeed.niagara.com>...

Bill Does the set chirp when you plug it in ?

If not check that resistor off the Big Filter cap
its a little 1/8 watt 1.2 m or something.

kip

Yes, the set chirps at plug in. All voltages are normal, except for

pins 5 and 6 of the eeprom which I'm seeking some opinions on.
Monitoring the two pins on the scope shows continuous activity, even
with a new eeprom. Thanks

Bill

--
"Watch the return E-Mail addy its false"
"Bill" <elect21st@aol.com> wrote in message
news:8fb59540.0404090313.4cb68588@posting.google.com...
Hello all- I have a CTC187 chassis that is completely dead. voltages
on the STK regulator are perfect. Pin 8 of the eeprom has 5v. However,
pins 5 and 6 have only 3 and 2.7 volts respectively, even with the
eeprom removed. Could this possibly be my problem ? I believe those
pins should be around 5 volts each. If so, does anyone know what can
cause the voltage here to go low ? I hate to replace the micro unless
I'm certain it is the problem. Thanks.

 

[Jason D.]

On 9 Apr 2004 12:53:28 -0700, elect21st@aol.com (Bill) wrote:

"john" <va3mmTAKEOUTTHIS@niagara.com> wrote in message news:<newscache$4wowvh$aca$1@newsfeed.niagara.com>...
Bill Does the set chirp when you plug it in ?

If not check that resistor off the Big Filter cap
its a little 1/8 watt 1.2 m or something.

kip

Yes, the set chirps at plug in. All voltages are normal, except for
pins 5 and 6 of the eeprom which I'm seeking some opinions on.
Monitoring the two pins on the scope shows continuous activity, even
with a new eeprom. Thanks

Bill

The pin 5 and 6 is also is one of two I2C buses from micro is
typically 4.xV But I typically see almost like 4.5V.

Anything lower you have problem. I find that one of IC is bad start
by unsoldering two pins on each IC hooked to the I2C bus or a nasty
glue under a SMD.

Cheers,

Wizard

 

[David]

Continuous activity with a new eeprom? Is it a clean data at 5v peak? If
not you have something loading down the I2C data bus.

Then do not overlook the horizontal drive circuitry, it is very common for
h-drive transformer connections to go bad, causing dead set.

David

"Bill" <elect21st@aol.com> wrote in message
news:8fb59540.0404091153.2a8560ee@posting.google.com...

"john" <va3mmTAKEOUTTHIS@niagara.com> wrote in message
news:<newscache$4wowvh$aca$1@newsfeed.niagara.com>...
Bill Does the set chirp when you plug it in ?

If not check that resistor off the Big Filter cap
its a little 1/8 watt 1.2 m or something.

kip

Yes, the set chirps at plug in. All voltages are normal, except for
pins 5 and 6 of the eeprom which I'm seeking some opinions on.
Monitoring the two pins on the scope shows continuous activity, even
with a new eeprom. Thanks

Bill


--
"Watch the return E-Mail addy its false"
"Bill" <elect21st@aol.com> wrote in message
news:8fb59540.0404090313.4cb68588@posting.google.com...
Hello all- I have a CTC187 chassis that is completely dead. voltages
on the STK regulator are perfect. Pin 8 of the eeprom has 5v. However,
pins 5 and 6 have only 3 and 2.7 volts respectively, even with the
eeprom removed. Could this possibly be my problem ? I believe those
pins should be around 5 volts each. If so, does anyone know what can
cause the voltage here to go low ? I hate to replace the micro unless
I'm certain it is the problem. Thanks.

 

[RonKZ650]

Check voltage on both ends of the on/off switch. If both pins have 5vdc then
99% of the time the eprom is bad. The LA7610 IC can also load the data lines
down and cause this. If one pin is 5vdc the other 0 then the eprom is working.
Ron