Orion MBR not charging

[manina]

Pins 8, 11 and 12 should be at the same voltage. Re-check to see if there was an error when measuring or if the voltage is actually lower on pins 8 and 12.

My mistake - pins 8, 11 and 12 all read the same 14,5V with an input voltage of 13,5V and output of 6,2

 

[Perry Babin]

What is the DC voltage across D1?

Is R11 within tolerance?

 

[manina]

R11 is OK

I measured D1 with and without the lamp connected. Is it normal I read voltage if I place the black probe on the cathode (red on anode) and on the anode (red on cathode)? The only difference is that is either positive or negative.

Anyway, with no lamp, the voltage is 16,9V while with lamp is 15,9V. This is without the jumper on IC2 pins 3/7.

With the jumper, voltage is 13,4 without lamp and 13,1 with lamp.

 

[Perry Babin]

That's a 30v Zener. Is the installed diode a 1N4751?

Has it ever been replaced?

 

[manina]

If I turn on the MBR70 without any load (no lamp), the voltage across D1 is 26,2V however, as soon as I connect the lamp, it drops to the values previously posted.

D1 is still the original one.

 

[Perry Babin]

What is the DC voltage loaded and unloaded on the striped end of D2?

 

[manina]

Without load is 29.2V while with load is 17.3V

 

[Perry Babin]

Does the DC voltage on IC1, pins 12 and 8 drop significantly from unloaded to loaded?

Do you have a scope?

 

[manina]

Pin 8 and 12 of IC1 has no significant voltage change.

I have a scope but a limited knowledge on how to use it

 

[Perry Babin]

Post a link to the owner's manual for the scope or post a good quality photo of the front of the scope.

 

[manina]

It's a DSO203

Seeedstudio Forum • View topic - DSOQuadV2.6 RESOURCE(Update 2012/04/12)

You can find a manual in the first post of this discussion. Counting from the bottom of the file list, it's the fifth

 

[Perry Babin]

Set the timebase to auto and the vertical amp to 5v/div. Ground the probe to the ground terminal of the amp and touch the probe to pin 9 of IC1. Post a screen cap of the waveform.

 

[manina]

This is the waveform with no load.

 

[Perry Babin]

Confirm that the tabs (or center legs) of Q3 and Q4 have the same signal. If they do, post a photo of the waveform on the tab of either transistor both loaded and unloaded.

 

[manina]

There is no difference between loaded and not loaded but there is difference between Q3 and Q4 - see attached files

 

[Perry Babin]

Set the scope to DC coupling (not AC coupling), 10v/div and post two photos. One with the probe on each end of D2.

 

[manina]

These are the two ends of D2 without load - with load they looks pretty the same

 

[Perry Babin]

Post the waveforms for Q3, loaded and unloaded. This time, make sure that the coupling is set to DC. You will have to set the vertical amp to 10v/div.

 

[manina]

number 1 is the unloaded while 2 is loaded

 

[manina]

I guess I have no hope to fix it