Re: Small questions that don't fit anywhere

1871
Tom Wanderer wrote: Tue Mar 26, 2024 9:18 am Best way to deal with bad connections on 1/4" unbalanced jacks.

I have a few unbalanced jacks on rack effects, mixers, etc. that are either noisy and intermittent and need to be fussed with, or don't reliably pass signal if pushed in all the way (Tascam line inputs). Contact cleaner? Re-tensioning of the contacts? Tiny bottle brush? I've been fucking with stuff like this forever but never sought a definitive approach.
Sometimes some contact cleaner sprayed on a male 1/4" plug and some vigorous thrusting will get them working again. Most likely, though, they need the solder joints reflowed, especially if they're PCB mounted.

Re: Small questions that don't fit anywhere

1872
Thank you, Nate. The particularly fussy jack in question is in an old EV rack mount reverb. Not PCB mounted thankfully. And the kind where the jack enclosure is shorter/doesn't totally enclose the contacts. So I had already hit it with contact cleaner and some vigorous thrusts, but it was also easy to re-tension the tip contact so I did that too. And it looked like there was some oxidization on the walls of the sleeve connection as well, so I hit those with more contact cleaner and worked a very stiff, short bottle brush in there. Don't think I'll get to test it again until tonight, but that's good advice to reflow the solder points if it's still giving me static.

It was one of those things that we've all encountered a million times and I either fuck with it until it goes away (cleaner and thrust) or get it set "just right" that I can get through the project. And I was like "why the fuck don't I just ask a professional?!" Your advice, as always, is greatly appreciated.
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Re: Small questions that don't fit anywhere

1877
Instantaneous power when starting might be higher than 30 mA. Are you measuring it with a scope or DMM? The sample rate of most DMMs is pretty low, like 2 kHz or something.

How much capacitance is after your rectifier stage? You could estimate inrush current based on that.

Or just forget all that and put something like a 100 mA fast-blo fuse in there and see if it powers up OK.

Re: Small questions that don't fit anywhere

1878
Nate Dort wrote: Sat Mar 30, 2024 1:03 pm Instantaneous power when starting might be higher than 30 mA. Are you measuring it with a scope or DMM? The sample rate of most DMMs is pretty low, like 2 kHz or something.

How much capacitance is after your rectifier stage? You could estimate inrush current based on that.

Or just forget all that and put something like a 100 mA fast-blo fuse in there and see if it powers up OK.
thanks Nate! I measured with a DMM. I'll ignore all the estimating and do the the try and error method.
I think I "over fused" the preamps quite a bit in the past!

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