Emax

Thanks Jack, I took out the digi board and ran an iron over the CD4028 and the Scanner chip connections, fault is still there. Also removed and reseated scanner chip, fault still there.

I reckon it is an internal fault on the scanner chip or the CD4028. I'm looking for +5 at the connections 2, 3, 14, 15 on the CD4028. The inputs from the scanner chip I think are 10 and 13, was getting the same 'low' reading on both of them when I checked.

Any more info would be great. Can get a  CD4028 at Farnell, but £20 minimum spend so want to know that'll fix it.




--- In emax@yahoogroups.com, "jack" <jammie.emma@...> wrote:
>
> ill check on sunday as im doing some burn in tests for a vfd so i can check the signals with a logic anyliser and check the voltages for the diodes could have a cold joint some where 
> 
> il;l let you know tomorrow what i find
>   ----- Original Message ----- 
>   From: mcnik_k 
>   To: emax@yahoogroups.com 
>   Sent: Saturday, November 05, 2011 4:28 PM
>   Subject: [emax] Re: Most front panel buttons don't work - Emax 1 Rack HD
> 
> 
>     
>   Yes, continuity checked for all voltage supply lines to switches.
> 
>   Fault is definitely pre-diode on the main digital board. All 4 diodes should have +5 at their chip-facing side, three of them have near zero, only one has +5, that is the one that supplies the aforementioned working switches.
> 
>   Thanks!
> 
>   --- In emax@yahoogroups.com, el macaco <elmacaco@> wrote:
>   >
>   > Did you check continuity on the traces carrying the power to the switches etc?
>   >
> 
> 
> 
>   
> 
> [Non-text portions of this message have been removed]
>