FDeck HPF has gone pop.

[Maude]

Hi all, I need a little help please. 

I have an FDeck HPF which went pop at last night's rehearsal. I'd plugged it into the power and a few seconds later I heard a small pop (from the HPF, my amp's volume was down) and then a few wafts of smoke came out of the jack sockets. 

I've opened it up and was surprised at just how simple it is inside. 

Now I'm far from an electrician, in fact I consider most electronics witchcraft, but can happily solder in new parts if it's simple, which luckily it is. 

I was hoping/expecting to see a capacitor with the top popped open but at first glance I couldn't see anything. Then I noticed that one off them looks swollen and lop sided, but not split. 

Would you assume this is not right and most likely the problem? I've ringed it in red. 

I don't know how to test a cap. 

 

Edited November 3, 2023 by Maude
Desperately trying to sort apostrophes before Dad sees.

[Maude]

It's a 220uf 16v.

Do I need anything specific or will any cap with those specs do the job? 

What is the temperature relevant to, the range it's happy to function in? 

Sorry for all the questions and thanks in advance advance for any help. 

 

[Wilson_51_]

Should be good just getting a replacement Electrolytic capacitor. Probably cost more on shipping than the cost of the capacitor. 
 

I would wonder why it went in the first place.. did you run it at 18v? 

[Maude]

1 hour ago, Wilson_51_ said:

 

I would wonder why it went in the first place.. did you run it at 18v? 

I also posted in the HPF thread and had the same reply/question. 

I hadn't even thought why up til now but you're both right(ish). 

The band I use upright bass in, and the FDeck, hasn't gigged for a few years but we're back up and running and have a gig in a couple of weeks. 

Yesterday was first rehearsal through the PA. I sometimes use a BBE Acoustimax preamp and put the FDeck in the same case, along with the other power supply. After your questions I realised I'd used the BBE's  power supply which is 12v. 

I guess that was enough to fry it although it's a 16v cap? As I said, I don't really understand electrics, but I'm happy to just solder in the new cap as long as I get the right one. 

[paul_5]

Just make sure that when you solder the replacement in that you solder the cathode (negative leg indicated by the white stripe) facing the same way; some capacitors aren’t fussy about polarity, these ones are. 

[Maude]

Are there better quality ones to go for or are they all much the same. 

Obviously they're cheap so buying the best won't break the bank. 

[JapanAxe]

The BBE Acoustimax takes 12V AC, so half the time your HPF was getting the wrong polarity and that will be what’s killed that cap.

 

Electrolytics can be sourced cheaply on eBay but it’s worth going to a reputable supplier - I buy mainly from Switch Electronics or DM Components.

[chris_b]

Message FDeck himself on Talkbass.

 

He'll be able to advise.

[nekomatic]

11 hours ago, Maude said:

Are there better quality ones to go for or are they all much the same. 

Obviously they're cheap so buying the best won't break the bank. 

 

The main difference in specs between electrolytics of the same capacitance and voltage is the temperature rating and lifetime - the cheapest ones are usually rated 1000 hours at 85 C, more expensive ones for longer at 105 C. If that lifetime sounds short, AFAIK it is quoted at the maximum voltage and temperature, so at room temperature and less than max voltage it should last much longer.

 

If you have a look at suitable capacitors on CPC (you may need to adjust the filters on the left hand side) you can get one that meets the specs for the princely sum of eight pence (plus 4.99 p&p, unless you order some other gubbins), or you can pay a bit more for a higher spec brand name one which since they are so cheap, I probably would. 

 

It's worth bearing in mind though that although one component has obviously failed, others may have been taken out by the AC supply as well - the resistors and ceramic caps will be fine but possibly the other electrolytics and the transistors. Unfortunately the JFETs aren't so easy to get hold of nowadays.

Edited November 4, 2023 by nekomatic
CPC link doesn't keep all the filter values

[pete.young]

Had a look in my bits box but I don't have a spare one of these. You could try asking in the DIY Effects thread if anybody has one they could send you - 5 quid postage for an 8p capacitor seems a bit off.

[nekomatic]

You’ll be able to find the cap elsewhere, including on eBay - I just linked to CPC because they have a good range and good data. 
 

I’d probably replace all three of the electrolytics to be on the safe side, then if it still didn’t work move on to unsolder and test the transistors. 

[Bassybert]

17 hours ago, Maude said:

It's a 220uf 16v.

Do I need anything specific or will any cap with those specs do the job? 

What is the temperature relevant to, the range it's happy to function in? 

Sorry for all the questions and thanks in advance advance for any help. 

 

Hang fire on ordering one, I might have one in my box I can send you. Will go and check in a bit. 

[ahpook]

6 minutes ago, Bassybert said:

Hang fire on ordering one, I might have one in my box I can send you. Will go and check in a bit. 

 

Ha, beat me to it !

 

 

Edited November 4, 2023 by ahpook

[Maude]

26 minutes ago, nekomatic said:

You’ll be able to find the cap elsewhere, including on eBay - I just linked to CPC because they have a good range and good data. 
 

I’d probably replace all three of the electrolytics to be on the safe side, then if it still didn’t work move on to unsolder and test the transistors. 

This sounds like a good idea as parts are so cheap. I've found a pack of 15 220uF 16v 105°c for 99p and £1.69 postage, so the other two (maybe the same rating, I haven't checked) won't add much to the cost. 

[Maude]

8 minutes ago, Bassybert said:

Hang fire on ordering one, I might have one in my box I can send you. Will go and check in a bit. 

That's very good of you, thank you. 

I'll hold off but I might replace more (see above) in which case I'll order some as they're cheap enough including postage from ebay. 

[Maude]

11 minutes ago, Bassybert said:

Hang fire on ordering one, I might have one in my box I can send you. Will go and check in a bit. 

 

4 minutes ago, ahpook said:

 

Ha, beat me to it !

 

 

The forum at it's finest, thank you both. 

[Maude]

@pete.young @Bassybert @ahpook thanks for all the offers, they really are appreciated, but I've just ordered from ebay.

I can get a pack of ten of each (the other two are the same rating 10uF 25v) for little more than a stamp would cost.

 

Thanks for everyone's input and hopefully it'll be back up and running soon. 

[Bassybert]

No problem, I've just checked and I've got 2.2uf and 22uf but not 220uf anyways 🤣

[ahpook]

48 minutes ago, Maude said:

@pete.young @Bassybert @ahpook thanks for all the offers, they really are appreciated, but I've just ordered from ebay.

I can get a pack of ten of each (the other two are the same rating 10uF 25v) for little more than a stamp would cost.

 

Thanks for everyone's input and hopefully it'll be back up and running soon. 

 

Great stuff ! Do keep us updated on the repair.

 

And welcome to Capacitor Club

 

 

[JapanAxe]

1 hour ago, ahpook said:

 

Great stuff ! Do keep us updated on the repair.

 

And welcome to Capacitor Club

 

 

What’s the charge for membership?

[Maude]

1 hour ago, ahpook said:

 

Great stuff ! Do keep us updated on the repair.

 

And welcome to Capacitor Club

 

 

 

22 minutes ago, JapanAxe said:

What’s the charge for membership?

 

Shhh, you know the rules. 🙊

[paul_5]

Rule one: don’t talk about capacitor club, just save all of your comments and questions until the end, then let them go all at once!

[Bassybert]

 

1 hour ago, JapanAxe said:

What’s the charge for membership?

Must ‘resist’ replying to such dad jokes 🤣

[Stub Mandrel]

Look up 'capacitor plague' on Wikipedia.

[Maude]

Ohm my, the terrible puns have started.