Scoreboard repair

[Milhousesmom]

Hello
I have a component with the marking
1117m3 0805L. It has a center pin ground and I cannot determine which specific component to buy. It does not have any letters preceeding the 1117 to tell me what type it is. Any help would be greatly appreciated.

Thanks

 

[bertus]

Hello,

It is most likely one in the LD1117 (ST) or LM1117 (texas) series.
(the texas datasheet is to large to upload)
See the datasheet for more info.

Bertus

 

[Milhousesmom]

Hello,

It is most likely one in the LD1117 (ST) or LM1117 (texas) series.
(the texas datasheet is to large to upload)
See the datasheet for more info.

Bertus

This data sheet show pin 1 as ground. Is there a version with center pin ground?

Thanks

 

[kellys_eye]

What makes you think your existing device is 'centre pin ground'?

 

[Milhousesmom]

Hello I am trying to repair a budweiser ice hockey scoreboard. This is a promotional item and only 15 were made so I am having no luck finding information on it.

The digits are not lighting up. There is a master motherboard and 3 slave boards. The master is getting the 12v in and is sending 12v to each slave. The accessories are getting the appropriate voltage but the digits are no lighting up.

The numbers are controlled by a part labeled HEF4511BT. The vdd on all of these chips read 1.7v.

There is a part labeled 1117m3 0805L that I believe is a voltage regulator. Pin 1 reads 0.5v pin 2(center) is ground and pin 3 reads 1.8v

There is a main ic labeled mkl25z128vlh4

Any help or suggestions would be greatly appreciated.

Thanks

 

[Milhousesmom]

Im not entirely sure it is. When I test it with the multimeter I get reads on 0.5v on pin 1 ground pin 2 and 1.8v pin 3. The tab on top has continuity with center pin and continuity to ground. Could this be my issue with my scoreboard not light up? There are 4 different boards with this same part on it and they all read the same. Thank you for your help.

 

[bertus]

Hello,

The images on the google drive don't show.
Upload the images to the forum.
Keep the size 300 kB max.

Bertus

 

[Milhousesmom]

 

[kellys_eye]

The regulated voltage is commonly on the main tab so your assumption could well be incorrect.

Given you have multiple boards with the same issue it would seem that the fault is OFF board and probably in the main power supply section. One of the pins on those regulators will be an unregulated input (say a 12V input, regulated by the device to a 5V supply) and if the 12V is missing then all the other pins will read wrong.

I'd guess the whole unit is powered by an SMPS supply and the fault will be there......

 

[kellys_eye]

What are you using for your reference ground?

 

[Milhousesmom]

this this test point. Is this the wrong thing to be using?

 

[kellys_eye]

I'm guessing that you number the pins left-to-right on the device as it appears in your picture? If so then the RHS pin is the input (normally) and will be a voltage higher than the expected output - not necessarily a lot higher as the device is called a low-drop-out regulator which means the difference between input and regulated output can be as low as 0.8V.

That said, I'd expect the output to be 5V and that's on the middle pin (or the large tab) with reference to 0V.

The 0V test point you show should be ok but test for continuity between that pad and the metal case of the SD card holder and/or the -12V pin on the connector adjacent to it.

Post a clear, up-close picture of the area surrounding the voltage regulator. Try not to get light reflections in the pic.

 

[Milhousesmom]

There is continuity between the test point and the SD card Case and also the -12v pin.

 

[73's de Edd]

Milhousesmom . . . . . . . . not using my usual lead in address . . . . just in case you are a mom . . . .

In reviewing / referencing all case profiles of that regulator . . . . . below . . . .


You are experiencing ground on the suspected REGULATED voltage out on the 1117 ' s center pin.
As for your reference to metering ground, I am suspicioning that your referenced ground circle, as well as the nearby negative pin on that
2 pin molex connector, as well as that card cages massive tinned housing would all be grounded.
Next noticed is that you sure have to plug on a WHOLE LOTTA connectors into that left front edge of the PCB !
How about doing some power down tests with your ohmmeter .
Now I don't know if they are running power to those 4511 drivers from a 12V source or if this 1117 is being either an adjustable unit or is a fixed 5V output.
Since your 1117 units final suffix markings are not using their expected protocol, with some additional 1.8-2.5-3.3-5 numbering also.
You have 12 and 6V on the board, can you confirm which connectors are feeding those voltages in ?
I see two left side connector sets, being referenced as power in and power outs . . .loop throughs, as well as that earlier metioned 2 pin molex near to your GROUND circle.
Also there is a marking on the PCB referring to a barrel power connector and its polarities.
If you use your 0.5V voltage readings, then pin 1 agrees with that pin being in an adjustable mode and connected to some resistors, and not being grounded.
Pin 2 should be your regulated output and NOT grounded .
Pin 3 should be the DC power input to be regulated, with that voltage suspicioned to be 12V.
and not that lowly 1.8 being experienced.
So o o o o o, in a power down condition, ohm from 4511 pin 16 power in and suspect a direct connection to pin 3 of 1117. If that is where the 4511 is being power fed from.
Then ohm from 1117 pin 3, to ground, if its pin 2 is at 0 volt potential, one might expect something pulling that pin 3 voltage down to that low of a value.
And that pin 3 being the HIGHEST voltage present, suggests that it is being the voltage input as per the data sheet, as well as the pin being a voltage adjust, as a voltage presence there suggests, its just that the regulated output . . .pin 2 . . . .seems to be shorted to ground.
I can't make much else out on the board . . .due to it being one of those bastardly black " APPLE" boards.
Can you ascertain if our 2 pin molex connector . . .by plug in . . . .plug out . . . procedure . . .. is being a 12v input or it is outputting 12 v from it ?


73's de Edd . . . . .


.

 

[bertus]

Hello,

Could it be that the middle pin is not connected?
The tab is also the output of the regulator:

Measure at the tab to check.

Bertus

 

[davenn]

I have merged 2 threads on the same topic by the OP
hence there will appear to be a little disjointed flow

 

[Milhousesmom]

I have traced a short from the voltage regulator to the mkl25z128vlh4 IC. When I remove the IC the short on the voltage regulator is gone and the center pin is no longer shorting to ground. When voltage is applied the scores light up but not steady lights.

All four boards have the same short. How possible is it for all four ICs to short at the same time? Could the regulators also be faulty?

Thank you for all the advice.

 

[kellys_eye]

That MLKetc device is a 64-pin device and not easy to solder IN let alone get OUT. How did you manage it? Cut the legs?

All four boards have the same short. How possible is it for all four ICs to short at the same time? Could the regulators also be faulty?

Does the regulator output rise back to its correct level with the defective chip removed? The MKLetc device operates fro 1.8V to 3.3V, not your usual 5V but since we're unsure of the regulators actual output anyway can you measure it and let us know what you find?

They are on-board programmed controllers so replacement is going to be 'impossible' unless you can find the boards OEM and get spares.

 

[Milhousesmom]

Output is reading 2.5v

 

[Milhousesmom]

Sorry output is reading 3.6v on the center pin on the master board.
4.5 volts on the slave boards.
Number generators are getting 4.9 v