Hello, I am trying to find the right capacitor replacements for the ones in the pic (Old Roland Synth). Having looked through your parts, I think I have selected the right ones, but need some clarification as I am no expert on caps.
I was advised to use Panasonic’s so from your parts, is my replacement part selection correct ? (PCE4332CT-ND, PCE3995CT-ND, PCE4344CT-ND)
If yes, I can order through Japan site as I live in Tokyo.
Many thanks.
Hi MJA,
Welcome to the TechForum!
You are correct in figuring out the voltage and value of each capacitor. They are 10uF 16V, 22uF 16V, and 100uF 6.3V. However, without more information, we cannot tell you whether the specific parts you selected are valid options, or not.
To be sure they will fit, we would need to know the diameter of each capacitor. Also, if you have maximum height limitations, you might want to measure that also, to be sure they will fit.
As a side note, there is no problem with selecting higher voltage parts as long as they have the same diameter. Additionally, you can look at the “Lifetime @ Temperature” specification to get an idea of the quality of the capacitor. Capacitors rated for higher temperatures and more hours are likely to last longer than ones rated for lower temperature and fewer hours.
Thanks David, this is awesome. The life and temp are rated at 1000hrs and 105degC which will be ok, but I hadn’t thought about size. I watched a vid on YouTube as with everything today and an synth engineer mentioned the Panasonic caps I listed worked well.
I will check the dimensions of the new parts I listed and if any issue I will come back. Best regards and thanks again
Martin
Just a quick follow up question. All the capacitors replaced and all seems to be ok, but I also noticed one of the surface mounted capacitors seems to be damaged and not in an easy place to fix. It is the same as the one in the photo C171, on the far left. According to the circuit diagram, it has a value of 0.1 which I assume is 0.1pF. Could this be replaced by another type of capacitor for easier soldering or will I need to create a surface mount somewhere else ? Sorry for basic question _
doh… 0.1uF is what I meant to type.
With a high value like 0.1uF you can replace it with a through hole part because the capacitance/inductance/resistance of the leads will not have measurable impact (if it was 0.1pF leads could be a problem).
Thanks Paul, Having done a bit more digging, problem is I can seem to find anything suitable that is not surface mount type for 16v 0.1uF (100nF). Happy for any pointers to any suitable through hole types.
With the current parts shortages there are no 0.1uF 16V ceramic caps in stock at Digi-Key.
However, with nearly all passive components you can use a higher voltage rating as long as it physically fits and you don’t mind that it costs a little more in 1 million piece quantities.
For low to mid-range ceramic capacitors the most common and usually lowest price in low quantity voltage rating is 50V. Here’s one radial lead and one axial lead part that are in stock.
https://www.digikey.com/short/t2qjbzn9
https://www.digikey.com/short/pv335tz3
For about a 40% higher price you can get this smaller 25V part.
https://www.digikey.com/short/m8zfdf0p
Good advice from Paul. The only thing I would add is that, if you can’t get a surface mount part in there due to space constraints, you should cut the leads on your capacitor as short as possible before soldering to the board.
The typical use-case for 0.1uF capacitors is to be a local (as in right next to an integrated circuit) source of electrons to feed that IC whenever it demands a quick burst of current. The traces in the circuit board and the leads of the capacitor add inductance, which impedes this rapid change in current. This, in turn, causes the voltage at the IC to briefly dip during high current demand. The shorter the lead length, the lower the inductive impedance, and therefore the better the capacitor will perform its duty. For some IC’s, it may not matter much, but others are more sensitive to this, so best practice is to minimize lead length.
Thanks Paul and David, all makes sense even for a novice like me and I actually have some 50v 0.1uF caps from something I was going to attempt a while ago. I will let you know how it all goes !!
