Recent Posts

1

Beginners / Re: identifying Ferrite bead value?

« Last post by Konkedout on Today at 05:18:59 am »

This is a difficult question.  I think ferrite beads are generally unmarked.

What do you mean by "blown"?  Is it physically damaged?  I don't think a ferrite bead will go bad unless it is physically damaged.

They are made of different ferrites so even with fixed dimensions, different types can exhibit different characteristics.

I am not certain why an audio preamp would have a ferrite bead.  One possible explanation is to reduce sensitivity to radio frequency fields.   I had an amateur radio license and a single sideband transmitter when I was young.  Our living room stereo audio equipment would produce loud garbled audio if it was operating while my transmitter was transmitting.  This falls into the broad category of Electro Magnetic Compatibility (EMC).

2

Repair / Re: Please help, how can I adjust this transistor?

« Last post by Harry_22 on Today at 05:15:14 am »

Yes your new video eplains my suggestion somewhat.
Now please measure voltage at two points:

3

Power/Renewable Energy/EV's / Re: Determination of solar panel life from Power/Impedance plot?

« Last post by jonpaul on Today at 05:13:44 am »

Your plot calculated from  of the panel  V, I or incremental internal resistance delat V/delta I?

It seems to be a simple arti=thmit fincetion of P, V, I , R and no relation to the panel life.

We have seen solar panel life depends on


Type of panel construction, quality of mfg eg cheap Chinese or Panasonic, Samsung, etc,

The solarisation degradation is between 3%/yr t 0.5%/yr for most panels depends on the above and the integrated solar intensity over the years.

Consult the panel mfg specs and the  integrated solar intensity  for your location.

https://en.wikipedia.org/wiki/Solar_irradiance

Jon
 

4

Repair / Re: Tektronix DM501A repair

« Last post by Rax on Today at 05:13:22 am »

What I do have at hand from the MG range of products is 404B and 401B (obviously the latter doesn't apply).

I'll give a shot to the 801B product, though the price is on par with the Cadillac of this stuff (Deoxit).

5

Repair / Re: Tektronix DM501A repair

« Last post by Rax on Today at 05:10:19 am »

I glue the needles in place so that they do not leak where they attach to the bottle top.

What do you use for this? I've considered taking this course of action, but been a bit apprehensive about contamination of the contact conditioner from the glue - so I'd be interested in your pick for glue.

6

Power/Renewable Energy/EV's / Re: Wire tracing - what to use as earth/ground in apartment?

« Last post by jonpaul on Today at 05:07:05 am »

 

Depending on your location and the local electrical regs, a safety earth  should be on the electric sockets, metal  frames of appliances, cold water pipes.
professional circuit tracers like Ideal, Fluke use a RF TX that lugs into a socket and a contactless probe.

No earth or grounds are used.
Jon

7

Computers / Re: Choosing DDR3 double channel slots when installing memory

« Last post by magic on Today at 05:04:47 am »

If all four sticks are single rank,  then it doesn't matter.  If the 4 GB sticks are dual rank and the 2 GB are single rank, I'd put the 2 GB sticks on one channel (slots 0 and 2) and the 4 GB sticks on the other channel (slots 1 and 3)

Why would that be?
Did you ever find it to make a measurable difference for any particular workload?

8

Repair / Re: Foaming electronics-safe spray cleaner

« Last post by David Aurora on Today at 05:02:51 am »

as seen here
https://youtu.be/4dSBP1dQSdo?t=433
I have some higher end Wurth glass cleaner, designed to remove bugs from windshields, that foams up and dissolves like that but I don't think it's safe to use on electronics.
What's that blue can?

Damn that looks like it would make my life MUCH easier sometimes

9

Beginners / Re: identifying Ferrite bead value?

« Last post by jonpaul on Today at 04:58:10 am »

select from Fair-Rite/TDK, EPCOS etc by the size and shape.

Just jump a wire for now, you will see no difference in the sound

Jon

10

Test Equipment / Re: Power supply for home lab - do I really need a R&S?

« Last post by jonpaul on Today at 04:57:01 am »

Dear Sr. Gomez:

Very fine and detailed post.

We can assit you better if you can precice your applications and experience:

eg: you are Beginner, amateur radio, techincial, emgineer, ?

uses: Testing and developing microcontrollers?
General analog circuits?
Batterty charging?

As a hobbyest since 1950s and Electrical enginer since 1968, we always used HP, Lambda, Tek dual or triple linear supplies with analog meters.

We have paid $US 10..50..75..and $250 max.

We found thewm on epay, Ham radio fleas, local asds like craig list etc.

We have no idea for the Chinese or Rhode and Schwartz you seem to be prefering.

We are wary of fancy digital controlled PSU as they are no as reliable or robust compared to simple linear.

Bon chance


Jon