Circuitbenders Forum

Circuitbenders Forum => Drum machines => Circuitbending discussion => Alesis => Topic started by: JZA on November 14, 2014, 01:47:16 AM

Title: HR 16 issue - frozen on power up
Post by: JZA on November 14, 2014, 01:47:16 AM
I just had a HR16 given to me and have experience with dmx drummachine and eprom programming ..

 i had to source a power supply, after reading these threads , i felt confident in using a spare psu i had around in a box , its 12v AC 1000ma (1a)

so the first time i turned on was happy until i noticed no button made a difference !

it said SELECT PATT 20 but no matter what i pressed it remained the same ,

i then checked the internal battery 3.6v then tried resetting it via ERASE DELETE RECORD short cuts, then took out various chips one at a time to maybe reset sram .. but no difference .except the display now reads SELECT PATT 00 .. so i obviously reset the memory when taking out the chips i assume, i read a few similar faults on peoples threads  and decided to upgrade the OS from 1.06 to 2.0 ... but no still difference .

any thoughts please people ?

thanks JZA
Title: Re: HR 16 issue - frozen on power up
Post by: JZA on November 14, 2014, 03:02:47 AM
hmmm i just squeezed the buttons really hard and they  do work !!!

i took it appart and looked for a dodgey connection or some sign of problems , but nothing so i gave it a good clean and got some dust out of it ,,,, its a bit better now but still have to press harder than i would b happy with ??

any thoughts ??

yes its the same for the sound buttons too , im scared i might break it pushing so hard ... if it were just a couple of buttons i would presume dirt , but every button ??

i even tested resistance on most of the solder traces and all seem fine ...

anybody know where to get schematic pleASE

thanks ~ JZA
Title: Re: HR 16 issue - frozen on power up
Post by: JZA on November 14, 2014, 04:18:49 AM
ahh found this in the service manual , will try tomorrow :

7.11 Old Keypad PC Boards
Revision A
 The original HR-16 came with standard PCB
type contacts (tinned copper traces), but these
were found to oxidize over time. This was
especially evident when the unit was used in a
moisture rich environment (such as near the
ocean). We have since switched to using PC
Boards with carbon contacts. We recommend
replacing the older type PC Boards with the newer
variety. In the event that the newer board is unavailable (emergency rushes, etc.) it is possible to
clean the old keypad contacts with a pencil eraser. While this will restore operation to the unit, such
a measure is strictly temporary, as the contacts will eventually reoxidize.
Title: Re: HR 16 issue - frozen on power up
Post by: Circuitbenders on November 15, 2014, 10:32:03 PM
HR16 buttons are incredibly prone to becoming intermittent

The best way i've found to sort them out is to clean the board contacts with isopropyl alcohol and in more serious cases, wire wool.

You can add some wire glue or conductive paint to the button side contacts if they are still having problems.