The No.1 Website for Pro Audio
Problem with my SPX90
Old 8th December 2011
  #31
Lives for gear
 
Ike Zimbel's Avatar
 

No worries...it's been my experience that you can't go wrong by rocking!
iz
Old 15th December 2011
  #32
Lives for gear
 
LeeYoo's Avatar
 

Read the other SPX90 post.
Old 22nd December 2011
  #33
Here for the gear
 

spx90 psu

Are three L6,L5,L4 caps? and if not what are they ? my L6 is totally burnt and it seems the other caps are not leaking and ok....any rate no power ...little help
thanks
Old 22nd December 2011
  #34
Lives for gear
 
LeeYoo's Avatar
 

Hi
L4, L5, and L6 are inductors, to remove any high frequency ripple left on C19, C21 and C23.
If L6 is totally burned, but still has continuity, the supply would still work, but with a slightly higher ripple on the +5 rail. Non critical component.
You could replace with any inductor of the same size or bigger that can handle the current of the +5 rail. Or even with a wire link, at the cost of slightly higher ripple.
Leo..
Old 14th January 2012
  #35
Gear Head
 

Choke replacement?

Hi, so although I earlier boasted of fixing 4 of these, one of them did not last. Turns out couple solders are cold/broken due to some sort of leakage/corrosion. One of the problem solders is on a 20uH choke and I'm having trouble even desoldering the component because of all the crap around it. Ultimately, I may need to replace the choke because I'm not sure the leg will survive the removal. I think I found the appropriate part at my local electronics store, but I am not sure since it *looks* completely different.

The existing part is L6, one of those dark green cylinders in the pics earlier in this thread. The only marking on it is 200k, which I take to mean 20uH (consistent with the schematic), 10% tolerance.

The part I have is packaged as "RF CHOKE 22uH, Q 50 MIN, 410 mA DC". It looks like a resistor and it has red-red-black-gold bands.

So, is there a problem with using a different construction of choke? And is the amperage or other ratings a problem?

PS. I was following this thread but completely missed LeeYoo's post... until now. As I'd rather not have the ripple, my question still stands as to whether or not this component will work.

Last edited by jumunius; 14th January 2012 at 07:52 AM.. Reason: reread thread
Old 14th January 2012
  #36
Lives for gear
 
acreil's Avatar
 

I suspect it should be ok, if the current rating is adequate. It's supposed to be an RF choke (i.e. attenuating high frequencies), so that's what you want.
Old 15th January 2012
  #37
Lives for gear
 
LeeYoo's Avatar
 

Those series chokes come in different shapes and sizes.
Two things are important. The value (in uH), and the DC resistance.
The value has to be about right ofcourse (and slightly more is better).
And the DC resistance as low as possible, to handle the current draw.
Higher DC resistance is more heat, and lower resistance is a bigger body that might not fit.
Leo..
Old 15th January 2012
  #38
Gear Head
 

Quote:
Originally Posted by LeeYoo View Post
Those series chokes come in different shapes and sizes.
Two things are important. The value (in uH), and the DC resistance.
The value has to be about right ofcourse (and slightly more is better).
And the DC resistance as low as possible, to handle the current draw.
Higher DC resistance is more heat, and lower resistance is a bigger body that might not fit.
Leo..
Thanks. The packaging doesn't make resistance value clear unfortunately.

So as I'm unclear about the current usage of the +5 rail, maybe I ought to test the draw? Or would it be too daft to simply replace the part and feel whether it overheats upon being on for a few minutes?

And curiously, how does the use of a choke differ from a ferrite bead? Don't they serve the same purpose, i.e. HF attenuation?
Old 15th January 2012
  #39
Lives for gear
 
LeeYoo's Avatar
 

Don't stress too much about value and size. This is not critical here.
You just want a low resistance to reduce the heat. If the packaging is the same or larger, it's fine.
If unsure, measure resistance with a DMM. I would expect less than 1ohm.
Just a ferrite bead would not be enough to get the 20uH. A coil with several windings on some ferrite core is normally used.
Leo..
Old 11th August 2013
  #40
Gear Nut
 

Reviving an old thread...
Does anyone have ideas on the all vu meter leds lit? I have a unit that works fine but input vu leds are all lit. I replaced the electolytics in the psu and most of them on the main board so far. Also replaced L4 and L5. No luck on the meter working though. I also replaced the two caps on the front vu meter board but no luck with that either. Bad vu driver?? Might replace L6 as well?
Old 28th January 2014
  #41
Gear Maniac
 
HotSkillet's Avatar
 

Crazy enough, I turned mine on tonight to see a big puff of smoke roll out the front & back of the unit. Meters are lit up like a Christmas tree. If I can't fix it cheap it's going to scrap on the mighty ebay.
Old 28th January 2014
  #42
Lives for gear
 
LeeYoo's Avatar
 

Every electronic part seems to contain smoke.
When the smoke gets out, the part does not work anymore

Gear with burned parts or popped-top caps are the easiest to repair.
You can actually see or smell where things went wrong.
Pictures?
Old 28th January 2014
  #43
Gear Maniac
 
HotSkillet's Avatar
 

Quote:
Originally Posted by LeeYoo View Post
Every electronic part seems to contain smoke.
When the smoke gets out, the part does not work anymore

Gear with burned parts or popped-top caps are the easiest to repair.
You can actually see or smell where things went wrong.
Pictures?
I left it in the road case but I'll take some pics in the next day or so. It's too cold to be outside taking this out of a rack in 9 degree weather. First warm day, friend! Thanks for the quick reply.
Old 28th January 2014
  #44
Gear Nut
 
BradL8068's Avatar
 

I have 4 spx-90"s and all of the supplies have gone at one time or another.
The problems have been.
1) Caps (recapping fixed)
or in one case
2) Diodes... note those are high speed diodes standard will not work
or in one case
3) The heat sink mounted transistor.
Brad
Old 15th June 2014
  #45
Here for the gear
Looking for a value on diode D7 on the PSU board, mine is impossible to read.

THanks
Old 15th June 2014
  #46
Lives for gear
 
mjrippe's Avatar
 

Quote:
Originally Posted by Smellgoats View Post
Looking for a value on diode D7 on the PSU board, mine is impossible to read.
It is a 15DF2 or 15DF4 fast recovery diode.
Old 20th June 2014
  #47
Here for the gear
 

D7 replacement

I've replaced D6 and D7 with 1N4936 diodes.
Old 4th January 2016
  #48
Here for the gear
 

Quote:
Originally Posted by QuestingElf View Post
I've replaced D6 and D7 with 1N4936 diodes.

Thanks for that info !


Old 19th June 2016
  #49
Reviving this thread to thank everyone for the information, helped me to get another one going. I thought some pictures might help so I blogged it here:
Old 8th July 2016
  #50
Quote:
Originally Posted by madtheory View Post
Reviving this thread to thank everyone for the information, helped me to get another one going. I thought some pictures might help so I blogged it here:
Timely post as mine just went down. When I bought my SPX90II a year or so ago I quickly bookmarked this page for the day I'd need it.

Switched mine on yesterday and the top row of LCDs light fully (just blank though), bottom dimmed. Input meter correctly shows signal but nothing comes out.

Noticed only the relay on the left (when looking from the front) switches after a second on.


Anyway here's a few pics.

@ madtheory on your blog post you mentioned that main cap is bulging, is that from the top? Mine is similar but not sure if this is normal as it pushes down easily almost like it's mean to be like that.

The only obvious failure I can see is the R18, should I repair that first?

What's the best way to discharge the big cap (90v), would putting a voltmeter across it from the underside of the board do the trick?

I have seen precautions against fixing these sort of PSUs but other than the usual stuff with big caps (I have a Gyraf Pultec so already aware of the dangers of discharge) what else is there to watch out for?

Cheers



Old 8th July 2016
  #51
Display issues are symptomatic of PSU failure. Replace all electrolytics. And no, the big one is not meant to bulge at all! And yes voltmeter method will work. Be careful.
Old 8th July 2016
  #52
Quote:
Originally Posted by madtheory View Post
Display issues are symptomatic of PSU failure. Replace all electrolytics. And no, the big one is not meant to bulge at all! And yes voltmeter method will work. Be careful.
Thanks, will report back how it goes.
Old 8th July 2016
  #53
Btw I saw it recommended to get low ESR caps, Panasonic FM etc.. (Farnell here doesn't have the nichicon locally)

Out of these two I assume the FM are better, only negative being larger in height?


EEUHD1E471 PANASONIC ELECTRONIC COMPONENTS, Electrolytic Capacitor, HD Series, 470 µF, ± 20%, 25 V, 10 mm, Radial Leaded | Farnell element14

EEU-FM1E471L PANASONIC ELECTRONIC COMPONENTS, Electrolytic Capacitor, FM Series, 470 µF, ± 20%, 25 V, 8 mm, Radial Leaded | Farnell element14

Last edited by Jesse Skeens; 8th July 2016 at 06:19 PM..
Old 8th July 2016
  #54
Gear Head
 

FM are good, I used those in mine — should generally fit.

I’d definitely second the recommendation to replace all the big electrolytics in the PSU. This includes the bulging black one from the 2nd picture, but also all the ones in the first picture. There are two — one in the bottom right (C23?) and the other in the top left — which have some white and green stuff on the top. They look like they may have leaked. If you’re going in there anyways, you may as well ensure that all of the big ones are fresh.

You mentioned R18 — are you referring to the green ceramic cap surrounded by brown goo? (Maybe it’s C22? I don’t have the board layout in front of me.) R18 is a resistor and looks fine, visually. Ceramics rarely go bad but that one does have a weird texture to it. If you are placing an order anyways, you should pick up one of those too — they are cheap.

And FWIW the brown goo is old glue from factory assembly.

As for discharging capacitors, I think they may lose their charge by the time your Farnell order comes in, but as a precaution, there are plenty of how-to’s if you Google it.
Old 8th July 2016
  #55
Quote:
Originally Posted by jumunius View Post
FM are good, I used those in mine — should generally fit.

I’d definitely second the recommendation to replace all the big electrolytics in the PSU. This includes the bulging black one from the 2nd picture, but also all the ones in the first picture. There are two — one in the bottom right (C23?) and the other in the top left — which have some white and green stuff on the top. They look like they may have leaked. If you’re going in there anyways, you may as well ensure that all of the big ones are fresh.

You mentioned R18 — are you referring to the green ceramic cap surrounded by brown goo? (Maybe it’s C22? I don’t have the board layout in front of me.) R18 is a resistor and looks fine, visually. Ceramics rarely go bad but that one does have a weird texture to it. If you are placing an order anyways, you should pick up one of those too — they are cheap.

And FWIW the brown goo is old glue from factory assembly.

As for discharging capacitors, I think they may lose their charge by the time your Farnell order comes in, but as a precaution, there are plenty of how-to’s if you Google it.
Cheers for that. Yea I initially thought the brown stuff was a culprit until I read (and noticed) it was just glue.

Agreed on the white green stuff on the top of the caps. And yes was talking about the resistor at R18, it's the arch at the top that's corroded.

If anyone knows the value that'd be handy, otherwise I can hopefully tell from the bands if it's still intact enough to see.

I checked the schematic but didn't notice R18 in the parts list.

That green component is L5, the big one, R18 might look like a cap but that's just the corrosion on top that might make it appear so, the resistor itself is just off to the right side under the goo.
Old 10th July 2016
  #56
Gear Head
 

Quote:
Originally Posted by Jesse Skeens View Post
And yes was talking about the resistor at R18, it's the arch at the top that's corroded.

If anyone knows the value that'd be handy, otherwise I can hopefully tell from the bands if it's still intact enough to see.

I checked the schematic but didn't notice R18 in the parts list.

That green component is L5, the big one, R18 might look like a cap but that's just the corrosion on top that might make it appear so, the resistor itself is just off to the right side under the goo.
Ah yeah, now I see what you mean. That corrosion made it look like some old green ceramic cap, albeit one that wasn't looking so well.

My schematic says R18 is 1.5k. Good luck with it all!
Old 27th January 2017
  #57
Lives for gear
 
The Beatsmith's Avatar
 

Hi guys,

I bought an SPX90II a long time ago to use on a specific project, when mixing. It powered up OK and passed audio - I can't remember if I tested it then.

I just turned it on to finally use it, but it doesn't output audio. It lights up all ok, battery seems fine, and is receiving audio (meter is working). Actually does pass a tiny bit of audio if you boost it 30dB, but it's obviously got a problem.

I've googled around and found a load of threads and decided to post on this one - obviously it's either faulty power supply (likely) or possibly something faulty with the output.

I know nothing of electronics unfortunately, but the power supply board doesn't look too healthy to me. I read that the brown gunk is actually just glue that has heated up over the past ~30 years and not the caps 'leaking' gunk.

I've uploaded some shots of the board - is there anything obvious that any of you guys can spot?

To me, capacitor C19 looks like the top isn't completely flat, but I don't know how to test it. I do have a multimeter but am not sure what to look for.

Is the darkened PC board anything to worry about? Do I need to remove the board and show the underside?

I know I should take it to an expert, but I'm worried that it will cost more than it's worth to fix it!

Cheers,

Ed
Attached Thumbnails
Problem with my SPX90-spx1.jpg   Problem with my SPX90-spx2.jpg   Problem with my SPX90-spx3.jpg   Problem with my SPX90-spx4.jpg   Problem with my SPX90-spx5.jpg  

Problem with my SPX90-spx6.jpg   Problem with my SPX90-spx7.jpg  
Old 27th January 2017
  #58
Gear Head
 

Quote:
Originally Posted by The Beatsmith View Post
Hi guys,
To me, capacitor C19 looks like the top isn't completely flat, but I don't know how to test it. I do have a multimeter but am not sure what to look for.
By "not completely flat" do you mean flush against the board? That's not an issue. But if you mean rounded on top, that might mean it's leaking.

Speaking of which, take a look at the big black cap in the middle. You never picture it from the side but the top of it looks very rounded and bulging. If I see that right, that would be the first thing to change. Probably no need to test it if it looks like that.

It wouldn't hurt to swap all the bigger electrolytics (C19 etc) while you're at it, but it may not be necessary.

Overall the board otherwise looks pretty normal, but you could pull firmly on all the components to see if you can lift up a leg. Sometimes corrosion could eat away at a leg, and then you would be able to pull one side of the component off the board.

Note: Don't use too much force, just enough to confirm that the components are firmly soldered in place. Also, it's ok if things move/twist a little, it's just a problem if one side literally detaches.
Old 27th January 2017
  #59
Lives for gear
 
The Beatsmith's Avatar
 

Thanks so much!

The huge big black cap is supposed to be rounded, i believe, it's moulded like that.

I gave the parts a wiggle, nothing really moves at all. For C19 yes, i meant a very slightly rounded top compared to the other similar caps. I'll try to take a picture!

Cheers,

Ed
Old 27th January 2017
  #60
Quote:
Originally Posted by The Beatsmith View Post
Thanks so much!

The huge big black cap is supposed to be rounded, i believe, it's moulded like that.

I gave the parts a wiggle, nothing really moves at all. For C19 yes, i meant a very slightly rounded top compared to the other similar caps. I'll try to take a picture!

Cheers,

Ed
Mine's like that too. If you press on it you'll feel is squish down like it's rubber.
📝 Reply
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
🖨️ Show Printable Version
✉️ Email this Page
🔍 Search thread
🎙️ View mentioned gear
Forum Jump
Forum Jump