urgent help needed

[rochele1]

hi

i have purchased ST-804A from com-spec.com and i want to install on GM 300 motorola , the below link is the link of installation instruction but really i got confused what to do , i know for many of you this is basic question but for me is a huge confusion .

i really appreciate if someone learn me how to install it .

http://www.com-spec.com/selectone/appnotes/8213.pdf

ready to pay consulting fee , indicating where to connect cables of module on the gm300 also helps alot

Regards

 

[michy]

It looks like you have to connect the ST-804A to different points on GM300 board. You'd probably need a schematic of the GM300 and find where those components are, etc.

For example...

I'd assume that "JUNC. R887 & VR804" is the junction between Resister R887 and potentiometer VR804... etc.

And perhaps "JUNC. Q652 & R849" would be the junction between transistor Q652 and resistor R849?

J8-7 maybe Jumper J8, pin 7? I'd be curious to see the schematic, and identify these components.

There are some smart people on here though that can verify.

 

[rochele1]

It looks like you have to connect the ST-804A to different points on GM300 board. You'd probably need a schematic of the GM300 and find where those components are, etc.

For example...

I'd assume that "JUNC. R887 & VR804" is the junction between Resister R887 and potentiometer VR804... etc.

And perhaps "JUNC. Q652 & R849" would be the junction between transistor Q652 and resistor R849?

J8-7 maybe Jumper J8, pin 7? I'd be curious to see the schematic, and identify these components.

There are some smart people on here though that can verify.

Thanks , but the problem is that when i see the map of board og gm300 , i don't know what's the meaning of "CUT TRACE BETWEEN J8-13 & VR804" because vr804 is above the board and j8 is bottom of the board and there's no direct connection between them .

if someone mark on the circuit map of GM 300 for me it would be very helpfull , there alot of tiny components here and i got confused ,i scare i connect cables of the module to the wrong part or point on the board

 

[michy]

oops... VR is voltage regulator...

just noticed.

 

[michy]

There's got to be a trace to VR804 from J8-13..

Can you call the comspec support and get them to clarify that trace cut?

 

[llu727]

VR804 in that circuit is being used as overvoltage protection. You will find similar circuits throughout that radio. Its there in casr you plug the wrong thing into the external connector
That would be the right place to cut the trace.. it allows the tone encoder to stay on long enough for reverse burst.

 

[rochele1]

There's got to be a trace to VR804 from J8-13..

Can you call the comspec support and get them to clarify that trace cut?

i called them they say their tech guys left the company 18 months ago and the only datasheet they have is the link i put here

 

[rochele1]

here is the map of the circuit , the problem is that VR804 is in the top of the board , but J8 is at the bottom , i don't know where to cut

 

[SteveC0625]

hi

i have purchased ST-804A from com-spec.com and i want to install on GM 300 motorola , the below link is the link of installation instruction but really i got confused what to do , i know for many of you this is basic question but for me is a huge confusion .

i really appreciate if someone learn me how to install it .

http://www.com-spec.com/selectone/appnotes/8213.pdf

ready to pay consulting fee , indicating where to connect cables of module on the gm300 also helps alot

Regards

From what I read in this instruction manual for the encoder http://com-spec.com/selectone/manual/st-804a.pdf you should be able to make all connections via the 16 pin accessory connector without having to make delicate and risky connections to the circuit boards. You may have to do some programming changes if any of the programmable pins are used.

Check Batlabs.com for all kinds of detailed info on the GM300. repeater-builder.com also has lots of good stuff.

FWIW, very, very few add-ons require opening the case on Motorola radios with the 16 or 20 accessory connectors. Study the radio first, then the encoder.

 

[rochele1]

is this possible to guide me which pins i can use ? , the website you introduced has lots of information , and makes me more confused ,

 

[rochele1]

i have marked J8-13 and VR804 on the map of gm300 , but really it's not logical to one of them is in the above and the other in the bottom , how to cut the trace between them ?

 

[ramal121]

To make the encoder work as intended, you CANNOT use the accessory connector exclusively. You will need to follow the instructions to tap into the correct logic circuits on the board.

Using the app note and the board x-ray, you'll need to carefully solder the wires to the points indicated. The only mod needed is to break the trace for PTT. The PTT switch in the mic is routed to the PTT input of the encoder and then from PTT output back down to the board. This allows the encoder to detect release of the mic button and let the PTT hang long enough to send the ANI out and then shut down PTT.

If you look at the top (component side) of the logic board, there is a trace that leaves J8-13, travels parallel to the pins, underneath the screw hole and then ends at a feedthrough where it transitions to a trace on the solder side of the board. I would break the trace right where it comes off of pin 13. It is small and delicate. If you are not comfortable doing this you can also cut the wire from the mic jack board on the other side of J-8. The yellow PTT input would then connect to the wire going to the mic jack. That'll do the same thing, just more ugly.

 

[WX5JCH]

J is usually junction - a cable connection


Sent from my iPhone using Tapatalk

 

[cabletech]

And when all else fails, since you are so new to this type of work and as YOU said, "I AM SCARED"

find a local ham that may help guide you or take it to a radio shop and let them do it