From: Garey Barrell 
Subject: Re: [drakelist] DR-7 Display


Garey Barrell  made an utterence to the drakelist gang
----------------------------------------------------------------------
Mike -

These are Motorola ECL IC's.  They have been considered obsolete for 
years, and short of finding one in a junkbox somewhere, very difficult 
to come by.   The "parts brokers" have thousands, but they only want to  
_sell_  in thousands also!

You might try reflowing the solder, since sometimes a cracked 
through-hole or solder joint will present this way.

73, Garey - K4OAH
Atlanta

Drake C-Line Service Manual
http://hr99.home.mindspring.com/R-4C_Servicez/>



Mike Williams wrote:

> Thanks to all who offered advice on the digital display on my TR7 
> which was ( is) going bonkers.  The problem was that after an hour of 
> warm up the display would start to display random digits  very 
> rapidly.  The radio was still on frequency.  To complicate matters, I 
> tried the counter function with a wire in the back of 
> the ext  counter connector and switch set to EXT. for the external 
> counter function.  Sometime the counter display worked properly with a 
> 144 MHz signal input and sometimes not.  Tested dc voltages and tried 
> to signal trace but my scope's bandwidth prevented any solid 
> measurements.  Finally isolated the problem down to U9013 on the DR7 
> board by blasting it with freeze mist; repeated this test numerous 
> times with the same results.  Looks like a thermal intermittent.  Here 
> is the question;  anyone know where I  can find this chip?  MC 10138 P 
> is stamped on the top of the case and the Drake parts list just calls  
> it a 10138.  I have searched a few electronics sites with no avail. 
>  
>  
> Thanks much,
>  
> Mike W4DL

----------------------------------------------------------------------
On Behalf of Garey Barrell 
Submissions:        drakelist{at}www.zerobeat.net
Unsubscribe:        majordomo{at}www.zerobeat.net - unsubscribe drakelist in body
Hopelessly Lost:    majordomo{at}www.zerobeat.net - help in body of message
Zerobeat Web Page:  http://www.zerobeat.net
Brought to you courtesy of TLCHost.net  http://www.tlchost.net/
----------------------------------------------------------------------

---