Replacing PTC fuses with...?

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: lisa, luketeaford, Kent, Joe.

Post Reply
stoiker
Learning to Wiggle
Posts: 25
Joined: Sat Mar 30, 2019 3:30 pm

Replacing PTC fuses with...?

Post by stoiker » Wed Feb 12, 2020 1:32 am

I bought a Bastl Quattro Figaro kit some time ago and started building it the other day. BOM, schematic etc. can be found here: https://bastl-instruments.com/eurorack/ ... figaro#diy

Both 100mA PTC fuses are missing in my kit. Does anyone know if I can omit or replace them with 10R resistors or jumpers? Does that make any sense?

tx301
Learning to Wiggle
Posts: 12
Joined: Thu Nov 22, 2018 12:44 am

Re: Replacing PTC fuses with...?

Post by tx301 » Wed Feb 12, 2020 2:04 am

Yeah, you should be just fine soldering in a pair of resistors. Though you could try contacting them, maybe they will send you the correct parts.

stoiker
Learning to Wiggle
Posts: 25
Joined: Sat Mar 30, 2019 3:30 pm

Re: Replacing PTC fuses with...?

Post by stoiker » Wed Feb 12, 2020 1:55 pm

Thanks. Sure I can contact them, but if I can substitute parts easily that's totally fine for me. It's not a NOS Vactrol, expensive IC or whatever, so I'll just go for the resistors (which I have a few left from other projects anyway).

User avatar
synthetek
Wiggling with Experience
Posts: 438
Joined: Fri Jun 05, 2015 3:32 am
Location: Orange County, California
Contact:

Re: Replacing PTC fuses with...?

Post by synthetek » Wed Feb 12, 2020 5:42 pm

I have substituted PTC fuses for jumpers or 10R a few times if I am building something for myself , just dont reverse power it :deadbanana:

stoiker
Learning to Wiggle
Posts: 25
Joined: Sat Mar 30, 2019 3:30 pm

Re: Replacing PTC fuses with...?

Post by stoiker » Thu Feb 13, 2020 12:45 pm

I'll try my best not to. There are polarity protection diodes anyway, so it wouldn't be that bad if I did, right? My understanding was that diodes are for polarity protection and PTC fuses avoid damage from shorting the circuit. Am I wrong?

User avatar
emmaker
Wiggling with Experience
Posts: 484
Joined: Sat Mar 10, 2012 5:07 pm
Location: PDX

Re: Replacing PTC fuses with...?

Post by emmaker » Thu Feb 13, 2020 2:20 pm

stoiker wrote:
Thu Feb 13, 2020 12:45 pm
I'll try my best not to. There are polarity protection diodes anyway, so it wouldn't be that bad if I did, right? My understanding was that diodes are for polarity protection and PTC fuses avoid damage from shorting the circuit. Am I wrong?
Maybe, depends on how much current the module uses and how long it's turned on.

So just to be safe you want the fuses or resistors.

With reversed power the diodes are taking all current and if more current is being drawn then they are rated for the diodes can burn up. With the fuses they'll overheat and open protecting things. With the resistors they will either limit the amount of current or burn up and open the circuit.

Jay

stoiker
Learning to Wiggle
Posts: 25
Joined: Sat Mar 30, 2019 3:30 pm

Re: Replacing PTC fuses with...?

Post by stoiker » Fri Feb 14, 2020 10:48 am

Got it, thanks!

Post Reply

Return to “Music Tech DIY”