[Warren]

Good Job...

[criageek]

Is there a "Member of the Month" award on the Phorum?  If so, I'm nominating Warren!  I received the power transformer today and it looks great!

   

And it tests out great...all windings read the correct voltage.

You really went above and beyond Warren...thanks again!

Rich

[criageek]

Ok, I wanted to separate this into a new post, so I could give Warren his props!

The insulation on the black wires on the power transformer appear to be cloth, and they are brittle and cracking.  Can I get by with just running a sleeve of heat shrink tubing over each?  Or should I go inside the can and splice new wires on as far up as I can get?

   

Thanks,
Rich

[Radioroslyn]

If you are doing the black wires that makes sleeveing easy, only one color to find. Doesn't matter much if you replace or sleeve.

[criageek]

If you are doing the black wires that makes sleeveing easy, only one color to find. Doesn't matter much if you replace or sleeve.

Thanks Terry!

Rich

[jcassity]

i would replace, keep color coding to match any diagram call outs.

thats what i will end up doing on my transformer,, once i figure it out!

[jcassity]

interesting useful note on the rivit design.
you would never know this until one did what you did.

i will have to remember this... i bet these were simply hammered in at the factory.

[criageek]

i would replace, keep color coding to match any diagram call outs.

I replaced the black wires as far back as I dared try to go, inside the can.  The rest I spliced on new wires outside the can.

Rich

   
   

[criageek]

interesting useful note on the rivit design. ...i bet these were simply hammered in at the factory.

I agree.  I intend to reinstall them using an impact screwdriver.

Rich

[criageek]

I'm going to have to decide what I'm going to do about a fuse...size and location.  My plan is to mount it here:

   

What size should I use?  According to the Sam's documentation the primary of the power transformer is rated at 0.78A so I'm thinking 1.5A.  But I'll probably wait to make a final decision until I've done some testing and can measure what it typically draws, then fuse it at twice that amperage.  Should I use a slow blow?

Thanks,
Rich

[Mondial]

If you fuse it at twice the normal draw, it may not blow under overload conditions. Consider that a slow blow fuse will carry 110% of its rated current indefinitely, and may take two minutes or more to blow at twice rated current. You probably want to spec the fuse closer to the actual draw.

If the radio was drawing .78A I would go with a 1A slow blow. If the fuse is easily accessible you can experiment with the lowest rated fuse that holds under normal operation, which will give the greatest safety factor.

A fast blow fuse will give more protection, but will typically blow under the current surge at turn on. Raising the current rating of the fast blow will prevent turn on blowing, but the higher rating may not give overload protection, which defeats the whole purpose.

[criageek]

Thanks for the info Mondial.  My plan has been to use a fuse holder like the one on the left and mount it inside the chassis.  But you make a good point about experimenting to get the correct value, so perhaps I'll change my plan and use one like the one on the right...there's plenty of room.  My problem with mounting those is that I don't have the right tools to make nice holes in metal that large.

Rich

   

[klondike98]

Another fuse holder option is the twist lock holder seen as #1 on the following RadioDaze page:
http://www.radiodaze.com/fuse-holders/

[Warren]

I intend to reinstall them using an impact screwdriver.

FYI .. I don't think you really need to use an impact screwdriver. It might be to much. Those were made to be tapped in and will turn by themselves as they go in. That's why they had no cut in the head for a screwdriver to begin with.

[criageek]

Thanks Warren.

I have a curiosity question for anyone that can answer it.  Why am I the only one that has a "Warning Level:  0%"??  I figured it was because I was a "Junior Member" but now that I'm a full fledged member I still have it.

Rich