Just Sharing This Switch Mode Power Supply Woes - New Aerial/Mast head amplifier.

[RustySpoons]

Sounds like "corporate BS" to me - given what you experienced!

Primary Cct "Ripple" control = maybe, that says nothing about the effect of the lack of filtration on the mains lead conducted and radiated emissions !
Never known potting compound to have any screening function - except if it were to be loaded with enough metallic particles to absolutely "slam dunk" the Pri-Sec insulation!

I was going to reply there must be some magic epoxy but I bit my tongue.
And if it did have metallic particles it would then be conductive

 

[satelliteman]

Seeing the images, might be time for a change and go back to Blakes PSU's.

 

[RustySpoons]

Seeing the images, might be time for a change and go back to Blakes PSU's.

I will say the Wolsey/Triax one I got seems top notch.

 

[jeallen01]

Seeing the images, might be time for a change and go back to Blakes PSU's.

Hope that wouldn't be one from Blakes Seven - might be a "little" too large!

 

[satelliteman]

The old PSM112 had their place.

 

[RustySpoons]

The old PSM112 had their place.

Labgear are now doing a small SMPS as well now (PSUFC), looks very much like that Antiference one!
PSM11x were everywhere.

 

[RustySpoons]

So I opened the Wolsey/Triax WMA-WPS100

100x better, screened RF Can, Linear PSU so completely isolated from the mains and by nature no RFI/EMC etc.
Decent bridge rectifier, not 4 diodes that the bean counters would insist on! Nice plastics too (feels like fibreglass reinforced plastic)
Even has a moulded UK plug, the Antiference one comes with some really cheap mains plug that I swear has a fake fuse inside LOL.

 

[jeallen01]

So I opened the Wolsey/Triax WMA-WPS100

100x better, screened RF Can, Linear PSU so completely isolated from the mains and by nature no RFI/EMC etc.
Decent bridge rectifier, not 4 diodes that the bean counters would insist on! Nice plastics too (feels like fibreglass reinforced plastic)
Even has a moulded UK plug, the Antiference one comes with some really cheap mains plug that I swear has a fake fuse inside LOL.

View attachment 119547

Totally Agree - totally "old school" - because the date on that PCB is from 2011 - hope the ones currently being built are the same.

 

[RustySpoons]

Totally Agree - totally "old school" - because the date on that PCB is from 2011 - hope the ones currently being built are the same.

That was bought from recent stock, sometimes SMPS is just not the right tool for the job, nothing wrong with a traditional linear for some applications especially RF.

BTW here is the "Cheapo" plug on the Antiference, nice bare strand on the live though they did go to the effort of putting ferrules on the bare wire.
That fuse looks questionable however.

 

[jeallen01]

Certainly looks like a counterfeit "BS1362" fuse - see the regs here.

The counterfeits vary a lot - from a simple ceramic tube with a bit of fuse wire held in place by push-on end caps and no quenching silicate inside (had some of those whilst working for HP in the early 1980s - and they came from a gen HP subbie in Singapore!) to sophisticated "total lookalikes" purporting to be Bussman/Beswick items.

Another reason to report to TS/CAB (and ESF) immediately, it would seem.

 

[RustySpoons]

Certainly looks like a counterfeit "BS1362" fuse - see the regs here.

The counterfeits vary a lot - from a simple ceramic tube with a bit of fuse wire held in place by push-on end caps and no quenching silicate inside (had some of those whilst working for HP in the early 1980s - and they came from a gen HP subbie in Singapore!) to sophisticated "total lookalikes" purporting to be Bussman/Beswick items.

Another reason to report to TS/CAB (and ESF) immediately, it would seem.

Im tempted to cut it open and see if there is any sand inside, it does have BS1362 underneath but anyone can write that on it.
Alarm bells ringing as its an "Unbranded" fuse and looks iffy.
Yeah think I might do that...

 

[jeallen01]

If you have a very low weight capacity weighing scales (or possibly even a stylus scales?) you could compare a gen fuse (I'm sure you have some) with the "suspect".
Edited to correct the terminology!

 

[RustySpoons]

If you have a very low weight capacity weighing scales (or possibly even a stylus balance?) you could compare a gen fuse (I'm sure you have some) with the "suspect".

I do in fact have digital scales for my stylus! I have lots of genuine fuses here... Will find a 3amp fuse and weigh it now.

 

[RustySpoons]

@jeallen01
I think this speaks for itself.

 

[jeallen01]

@jeallen01
I think this speaks for itself.

Unfortunately "job done" - the "3A" fuse doesn't have any sand/silicate inside. Time to report!
PS: FWIW, I did a number of tests at HP on those fuses - put them in a plug, plugged that into a 13A skt on a commercial ring main cct (so 4 sq mm cables and probably a higher-rated CB in the distribution unit), and then turned the switch ON.
Result? Varied from absolutely"nothing" to a relatively big flash and smoke and a lot of carboniferous deposits (which could result in internal tracking) inside the plug! Probably not "extremely dangerous", but very startling to anyone in the vicinity! Wish I still had the photos I took at the time

 

[RustySpoons]

Unfortunately "job done" - the "3A" fuse doesn't have any sand/silicate inside. Time to report!
PS: FWIW, I did a number of tests at HP on those fuses - put them in a plug, plugged that into a 13A skt on a commercial ring main cct (so 4 sq mm cables and probably a higher-rated CB in the distribution unit), and then turned the switch ON.
Result? Varied from absolutely"nothing" to a relatively big flash and smoke and a lot of carboniferous deposits (which could result in internal tracking) inside the plug! Probably not "extremely dangerous", but very startling to anyone in the vicinity! Wish I still had the photos I took at the time

Sounds like you had/have a very interesting career.
I used to work for HP myself and went to some fantastic places, was frequently in Germany at many of their offices.
Their canteens at HP Germany would put a Michellin Star restaurant to shame and I will never forget the size of the Asparagus!
Saw some crazy products that were never released or were way before their time.

 

[jeallen01]

@RustySpoons
Yes, I did have a very "interesting" career (might put a link to my LinkedIn profile tomorrow!), but I could have done with a "less interesting" one as I might then not be suffering the blood pressure issues that I now have!

Anyway, went to HP in Germany several times for regulations conferences and so on (and a 5 week stretch in Boise and the West Coast sites ) - very good, and quite a lot of very good German wine (Red, even!).

 

[RustySpoons]

@RustySpoons
Yes, I did have a very "interesting" career (might put a link to my LinkedIn profile tomorrow!), but I could have done with a "less interesting" one as I might then not be suffering the blood pressure issues that I now have!

Anyway, went to HP in Germany several times for regulations conferences and so on - very good, and quite a lot of very good German wine (Red, even!).

I deleted my Linked in as I was sick of being harassed by companies. I left there due to stress, I now suffer Migraines since... So can understand where you are coming from. Ironically when I try and apply for a less stressful job I get declined as I'm over qualified and over experienced!
Yes HP were very good at taking you out for some wine and decent food, I drank a bottle of Red wine at an evening meal and ordered a beer, the waiter came over and asked if everything was okay. I said why wouldn't it be, they commented that I had consumed a bottle of Red wine and asking for a beer, would I like medical attention! I said no I'm fine I'm British. I guess it's not the done thing over there!

 

[jeallen01]

Night, Night All - time to "destress"

 

[RustySpoons]

Night, Night All - time to "destress"

Same here! This PSU has got me quite worked up
Night to you too.