SOLVED HAARP Settings all sound the same

[Hexjibber]

Hi there,

Got an issue with a HAARP build where switching between the rotary positions doesn’t actually change the arpeggio sequence at all. Well to be precise, positions 1,3,4,5,6,7 & 8 all sound the same and position 2 is different. Any ideas where would be a good place to start troubleshooting this one?

I’ve checked the components against a working build and it all looks ok, I’ve swapped the EEPROM from my working one but that made no difference. Apart from the rotary, everything else is working as expected. I tried reflowing the 1P8T pins but that had no effect. I’ve noticed the voltage regulator getting quite warm so wondering if that’s related? It’s not normally a good thing!

My best guess would be a fault rotary switch but really not sure where to start with this one as I don’t know what is really responsible for selecting between the arpeggiation programs?

Any insight or best places to take readings etc would be much appreciated

 

[zgrav]

you can check your switch to see if it is creating a connection between the center pin and a different one of the outer pins every time you rotate the pot to a different position.

If the rotary switch is working OK you can check the connections between the switch and the FV-1. If you look at the schematic in the build document you will see that the rotary switch changes the voltage going to the FV-1 by adding in diodes with each setting. that is why there is a row of diodes on the board underneath the rotary switch. you can use your meter to measure the voltage at the FV-1 on pins 16, 17 and 18 to see if the voltage changes on at least 1 of those pins every time you change the setting on the rotary pot.

 

[Hexjibber]

Hi, thanks for the quick reply, much appreciated! So from checking continuity on the switch pins it looks like the switch must be faulty as I only get a successful reading on pins 1 & 2, the rest are dud. Looks like I'll have to order another rotary! I'm guessing it's more likely to be the switch than the solder connections themselves?

 

[zgrav]

it is the switch if you are checking for continuity where the legs solder onto the board.

 

[Hexjibber]

Yes I realised that just after I posted it that I'm checking the pins on the switch directly so it must be that. Annoying that I've got a dud, but I suppose these things happen!

Thanks again for the advice and also info around how the switching between the FV-1 and diodes works, that makes sense and will help me debug in future if I still run into problems after a new switch.

 

[Robert]

Turn the rotary switch all the way counter clockwise then use a clip lead or jumper wire to connect the center pin of the rotary to each of the outer rotary pins one at a time and see if the modes change.

 

[Hexjibber]

Thanks for the tip! Yes the modes change if I jumper it, so presumably that confirms a fault with the switch?

 

[zgrav]

if you have a favorite setting you could temporarily jumper that connection and play with it while waiting on a replacement switch.

 

[Hexjibber]

This build is for a friend, I've already got my own one on my board I've ordered a replacement switch so should be here within the next day or two

 

[Robert]

Yep, sounds like a faulty switch.

 

[Hexjibber]

Just a quick update, swapped out the switch for a new and all working fine now, thanks again for the assistance