P5400 No Power

[Muxlow]

Ello ello

Iv got a Macom P5400 radio.
I have about 5 batteries and all hold charge and no problems with them.
The radio however will not power up.

Is there a fuse or spot on the board i can check to see if that has been blown or what not or anythign on the boards them self to have a peek at to see if there is a issue there or not?

When i power it up nothing happens on the screen and no sounds when i push buttons either

 

[greenthumb]

If you hook it up to a power supply that can tell you how much current is being drawn, do you see any current being drawn when you power it up? If so, how does the current change over time?

 

[Muxlow]

Where should i connect the volt meter to get these readings?

 

[ElroyJetson]

Skip to 3:30 for amp readings.

THE BEST Multimeter tutorial (HD) - YouTube

 

[Muxlow]

Oh i ment what part on the radio

On the battery, pop open the case and someplace on a board or..

 

[ElroyJetson]

You'd need to engineer a way to connect the battery to the radio using wires. The ammeter would take the place of one of those two wires.

 

[Muxlow]

I took a peek inside the case and connected the battery and used my Fluke 1520 MegOhMeter on the board where it connects to the battery. Its showing 8V on the 2 outside pins and 7 on the center

 

[MASTRTECH]

Check the reference oscillator. If it's dead, the radio will not power on..........

 

[Muxlow]

Can do. Where is that located

 

[Muxlow]

Is it on this board at all?

 

[LMR_Dude]

F401, is the fuse you are talking about. Looking your picture it is between the two battery contacts on the right. It is horizontal and near TP 202 (which is the battery monitor point). I suspect that the left side of fuse is the load side so check for voltage there.

Happy hunting.

 

[Muxlow]

Here is a little better shot. Im not seeing any of these numbers on the board.

If youd be so kind to circle them?


Iv checked the first horizontal fuse to the left of the battery pin and it had voltage. The next fuse that is vertical was fine too, the larger vertical one i got no reading

Were these the correct ones to check?

 

[LMR_Dude]

I've circled F401. The other components nearest it are a coil, cap and a diode. Just check F401 and leave them be.

That circle, left and low, as viewed from your second picture is TP 202, the test point for measuring voltage FROM the battery. If you have 7.5 VDC there then your battery and battery contacts are good. If you have 7.5 VDC on the OTHER side of F401 then you have more digging to do.

 

[Muxlow]

Okie doke

Just checked TP 202 and has voltage going thru it
Where is the F401 located now?

 

[LMR_Dude]

Check for voltage on the other side of F401 now by placing your probe on the contact pad of the diode to the right of the fuse. Its larger so you have a better chance of making solid contact and not damaging F401.

Ive also circled TP203, BATT GND, these points will give you solid contact.

 

[Muxlow]

When i connect my meter to the left contact pin from the battery and the otherside to the F401 i get a reading of 8 from both sides

 

[LMR_Dude]

Try chassis grnd for the neg probe just to be certain.

You can also try this now that you have ID's both sides of F401.

WARNING: REMOVE THE BATTERY

Set the meter to measure continuity and verify if the fuse is blown. One probe to TP 202 and the other to the diode. This test is not the greatest since the fuse is still in circuit but infinite ohms is a indication of a blown fuse while something close to zero generally indicates a good fuse. Checking components in circuit is tricky so that why I went with you looking for volts first.

 

[Muxlow]

When i do that for the F401 i get a buzz from the left side of it but not from the right

 

[Muxlow]

The one with the little S kind of thing on it is F401 correct?

 

[LMR_Dude]

I don't understand "buzz". Your meters indication of continuity?

With one probe on TP202 and the other on the diode, what does you meter read in ohms?