Cheers, will try them and see. Can't be worse than dead can it
Although they did make use of the small size components, they put them in larger screened units anyway, so should get away with it.Many thanks.
R.
Richie_asg1
Member
Last Activity: 05-13-2012, 01:49 PM
Joined: 02-09-2009
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Re: Alternative req'd for wet tantalum axial caps
Cheers, will try them and see. Can't be worse than dead can it Although they did make use of the small size components, they put them in larger screened units anyway, so should get away with it.
Many thanks.
R. -
Re: Alternative req'd for wet tantalum axial caps
Thank you for the quick reply. I have repaired some valve based equipment that had perfectly happy yellow polyester film caps in there so this looks good. The psu in the radio only has to supply 4 voltages from a 24v battery, but one of those is 110v with an inverter. I think it overshoots a bit then is regulated back down to the 110v. Without detail I think the electrolytics are there as smoothing caps on the 110v rail to 0v, and there are some more in the oscillator module just to keep things clean.
Is there any problem...Last edited by Richie_asg1; 01-09-2012, 08:10 AM.Leave a comment:
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Alternative req'd for wet tantalum axial caps
Hi folks,
I'm just sorting out a military radio built around 1970 with a failed PSU. This seems to be a common trend on this model. Problem I'm having is finding a replacement for the caps they've used which are axial 3.6uf 150Vdc wet tantalum with a metal can and red glass seal.
The thing is - a lot has happened since 1970, so is there a better alternative out there now - in this odball size?
The equipment is all sealed up and dry but can get quite hot, and these have lasted 40 years - will modern electrolytics last that long?
Similar types in the HF end... -
Re: First post, Benq monitor power issue?
As above but check with the computer feed in as well, as some won't do anything without this turned on. Goes into power saving mode eg. off.
If it obviously doesn't work, check the power transistors nearest the tube outputs as above, and look closely at their capacitors & solder joints.
Worth resoldering all the transformer pins as it only takes 2 mins to add a little and reflow.
This forum is great - has helped me a lot.Leave a comment:
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Re: Benq T701 17" 1 second on - then black.
Thanks for the links.
I've replaced the C5707 pair today, and reflowed the transformer joints. It only takes 2 mins to do - so I agree it's worth doing anyway. A couple of the pins were under tension - so it could easily be bad design leading to stresses at the pins when warm.
Original cap tested and put back. Would prefer to replace it, but no spares yet.
Anyway - it works now, and I'm using it now to burn-in and check it's not going to black out anytime soon.
Will get some FU9024 as spares....Leave a comment:
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Re: Is ESR meter worth buying
I've just built one on stripboard following plans online. I would give a link - but it no longer works! - good job I got a hard copy to work from. It was based on other peoples' works anyway. I had to cut the board in two to fit around the meter in the case (which is 60mm x100mm x 25mm, as the meter is quite deep. Not too big and bulky, and has a flap for the PP3 in the back.
You're right about not being too accurate for low ESR's ; Works fine for seriously dead caps at the moment and I'm still tweaking components to increase sensitivity....Leave a comment:
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Re: Benq T701 17" 1 second on - then black.
As those are Mosfets, I'm not too sure about testing them in circuit. I did probe them - getting first a reading of 25K and 2k, Grounded the pins with my finger then tried the second reading again, and it was in 26Mohm range - so I suppose this proves I'd latched it on for the first reading, then off for the second right ?
Can't seem to find replacements online for those two D10PF06.
I've bought a pocket microscope to check solder joints. Very handy for getting the dust off laser lenses...Leave a comment:
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Benq T701 17" 1 second on - then black.
Thought I would start a thread on this one for easier reference rather than hyjack another one.
[ATTACH]17777[/ATTACH]
[ATTACH]17778[/ATTACH]
Monitor flashes on for 1 second displaying logo, then goes out and turns off - no lights.
First prod around the inverter board showed 2 of the C5707 to be open circuit.(Q808 & Q809)
Transformer output resistances seem very similar, and solder pads seem ok.
What was deffinately not ok was the 220nf box capacitor (C826) between the transistors - which had cold solder... -
Identifying Soldering Faults
Just thought this is worth a look for examples of good practice -
[url]http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/601%20General%20Requirements.html[/url]
As a newbie to most of this. This kind of information is needed so we can spot a good one from a bad one.
Please post other example pictures in this thread as you see fit.
Other pictures from the net - copyright of their original owners.
(All of the above are actually bad)
Just thought this is worth a look for examples... -
Re: HALP! Where to store all of these Capacitors?
I bought an Apothecary Chest years ago - 42 deep drawers. Still keep things in zip loc bags in there as I'm not at the overflowing stages yet.
It just keeps all my other junk out the way - and looks nice in the living room.
Sometimes Auction houses sell storage that was used in libraries for microfilm or index cards. These would be ideal for lots of small items I would think.
Screwfix sell toolboxes designed to organise screws. Both sides open out - I think you get 25 compartments each side.Leave a comment:
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Re: Help on desoldering transistor
OOOhh.
I fitted one of these from Maplin last year. I thought as it said "ball bearing" it would be fine.
However - one year down the line my case was buzzing like box of bees - and it was because this fan had failed.
I took it apart - and found - no ball bearing - just a bronze bush, which was now badly worn.
If I had the money to spend, I would buy a new case with better cooling built in - and just transfer everything over.
I did buy a fan speed controller for my case...Leave a comment:
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Re: Help on desoldering transistor
Could you use a low melting point solder instead - There is one listed at 145 degree ?
Nice big blob - loads of flux and a jewlers screwdriver ?
Just thought it would be cheapr than a chip quik kit.Leave a comment:
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Re: Dell E172fpb
Have just picked up a Dell - E151FPb for rework.
Aparently "works ok for a bit - but have to keep smacking it"
Exhibited classic Transformer cracked solder joints.
Resoldered all inductors as there was signs of rings around more than one.
Works fine now.
This NASA website is great for good practice and faults in soldering -
[url]http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/601%20General%20Requirements.html[/url]Re: Dell E172fpb
Have just pickedLeave a comment:
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Re: Benq Inverter board C5707 Transistors
No flicker - just bright for a second or two - then blackout.
I'll stick with replacing the last two 1000uf 10v caps I didn't have last time, testing those FU9024N transistors and resoldering the transformers complete.
Will also check the CCFL's when I read how to do that.
Will report back how things go. Thanks for your help again. Great forum - great people.
...
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Re: Benq Inverter board C5707 Transistors
Thanks for the pointer BobDee - and Excellent photo by the way of cold solder cracking. Will resolder all transformer pins.
My symptoms are- works fine daily - for an hour or more, then display goes black - green power button stays on. turn off, turn on - will stay on for a few seconds before going black again. Leaving to cool results in good working again.
Display goes bright for 2 seconds before going black completely. Tried adjusting brightness - but has little effect. This rings a bell with something I've read -...Leave a comment:
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Re: Benq Inverter board C5707 Transistors
I'm normally on Fixya !
I am still trying to get to the biottom of my dell E173FPb
I bought 4 c5707 and the fuse from Ebay - replaced them anyway as the problem seemed only to occur when hot - and I couldn't test this.
Checked for any cold joints around the transformers.
Do your power transistors look hot - slight browning of the board around heatsinks ?
Anyway - replaced the 4 + fuse - and still had same problem.
Then replaced the major Elec' Caps - still...Leave a comment:
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Sony Camcorders - too many to list.
Just had a look inside a Sony Handycam CCD-TR55E, and found many bad electrolytic caps leaking all over the place.
Most are surface mount types 6.3v commonly, but there are a couple of leggy ones that are also rather gooey at their bases.
I don't think it helps that these units are exposed to humid areas on their travels, so any electrolyte leakage may go in any direction, and may attract more moisture.
Typical problems involve motorised mechanisms not getting power, or short bursts of power quickly fading.
I'll post photo's when I figure... -
Re: Emachines!! EMACHINES!! EMACHINES!!!
Hi folks.
Currently running on an Emachines 530 Pentium 4 machine. No faults - yet, so may have a peek next time I'm in there. Cooling sounds a bit noisy at the mo, so that will be before the summer.
Really joined the forum because of a sony handycam - that may have a notorious bad cap problem. Really came to learn from those who know about SMD's. Surprised that these can go bad as I thought SMD's were very robust. Now I find there are fake components out there
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