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Crowella 13th Jan 2019 12:39 pm

Philips SBC850 Multimeter
Hi, this is my first post, I have only just registered to the site so hope I am getting this right.
I have an old Philips SBC850 multimeter which I found in the bin. Cosmetically, it's almost like new and the analogue scale works fine. However, someone has used it on the wrong setting or something and fried at least 6 resistors. Would anyone know where I could obtain a circuit diagram since their values are unreadable? Thanks, Stephen

karesz* 13th Jan 2019 2:55 pm

Re: Philips Sbc850 Multimeter
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post a photo please!
Radiomusem knows only SBC-851, s I think the UTS-001 i.e. can be (very?) similar...

Crowella 13th Jan 2019 6:30 pm

Re: Philips SBC850 Multimeter
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Hi, and thank you for the quick reply. It looks to me that your SBC851 is a new version of the same thing, it looks very similar but close up the front has slightly different scales, and the pcb inside is totally different. However I appreciate the info as I have wondered for some time about using the sbc-851 to fix my meter.

giacomo16v 23rd Mar 2020 12:07 pm

Philips SBC 850 Multimeter
Good morning guys today I found a vintage multimeter, it was from my grandfather, the problem is that there is a burnt resistance. I tried to find information about this resistance on the Internet but only in this forum, in this page, a boy has a problem similar to the mine, and I think now I can help him a bit with the photos of my multimeter, because his has many more resistances burned than mine and I instead only have one burned. My invitation to him is to take photos with better quality, because his photos are blurred and not very magnified. So maybe let's fix two of multimeters ;) Anyway, any of you new, do you have any idea about the resistance you need? Have a good day everyone!

Station X 23rd Mar 2020 12:16 pm

Re: Philips SBC850 Multimeter
Hello giacomo16v and welcome to the forums.

It's been over a year since Crowella visited the forums, But you're welcome to post pictures here.

giacomo16v 23rd Mar 2020 3:03 pm

Re: Philips SBC850 Multimeter
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Sorry, my this is the foto:)

giacomo16v 23rd Mar 2020 3:47 pm

Re: Philips SBC850 Multimeter
I think the color of resistance are all brown for 1,2,4,5 ......the middle is to much burned and dont know if that is one information for understand commerce the only one resistance that you can find is one resistance all brown if the 1,2,4,5 are brown....somebody have an idea???

DMcMahon 23rd Mar 2020 4:22 pm

Re: Philips SBC850 Multimeter
Hello giacomo16v,

What make and model is your multimeter ? it looks similar but not the same as the Philips SBC850 photo.



DMcMahon 23rd Mar 2020 4:45 pm

Re: Philips SBC850 Multimeter
Are you able to view the other side of the board to see what components the burnt resistor connects to ?

Crowella 24th Mar 2020 5:01 am

Re: Philips SBC850 Multimeter
Hi, never did restore that old meter, however, I still have it, and intend to replace those resistors, when it burnt out, it actually created a dry/disconnected solder joint, therefore none of those resistors were destroyed, can't guarantee their accuracy though, I can measure the resistance for you. Would very much like to speak to you about it.

giacomo16v 24th Mar 2020 9:43 am

Re: Philips SBC850 Multimeter
Good morning crowella meanwhile I believe you can replace those burnt resistances with the good ones that are seen in my photo and then You should try to understand that last Resistance that burnt to me what kind of value it has.....For example, I know that for sale there are not all the values ​​of resistances imaginable, so it could be that, having the first, second, fourth and fifth brown stripes, it could be that the third is inevitably of a single color.....What do you think

Station X 24th Mar 2020 11:31 am

Re: Philips SBC850 Multimeter
Close up pictures (use macro mode if your camera has it) of small sections of the PCB would enable all the component values to be identified from their colour codes.

giacomo16v 24th Mar 2020 4:32 pm

Re: Philips SBC850 Multimeter
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This is the high resolution photo .... I also tried with a Wood lamp to see if under the burn I could understand what the written resistance was but I could not see anything
So the only possibility is to understand if with the 4 brown stripes that are on the unburned resistance, the central strip (the third one) can be of only one possible color, because maybe there is only that on the market.

Station X 24th Mar 2020 4:48 pm

Re: Philips SBC850 Multimeter
The writing denotes the type of diode fitted for example 1N4148.

Interestingly the two resistors connected in series have 13M7 ?? written under them which most likely denotes their combined value. It also appears that all the other resistors have their values written under them. If you snip out the burned resistor you may be able to read its value from the PCB.

giacomo16v 24th Mar 2020 4:54 pm

Re: Philips SBC850 Multimeter
1 Attachment(s)
Maybe like this the colors of resistances of the first one one the left, of before, are better. i've create one pdf 4000dpi resolution

giacomo16v 24th Mar 2020 5:03 pm

Re: Philips SBC850 Multimeter
The burnt resistance is disconnected and unfortunately it is not read under what is written, as the board is also burnt, as I said I also tried with a wood lamp to read under the burn but nothing appeared.

For the other resistances just do the calculation of the value from the colors as they are all intact. The only maybe that I will change is the one close to the white variable resistance, as it is well seen, which is a bit burnt underneath and perhaps, even if it is not like the other with all brown stripes, it has not kept its given value by the colors on the stripes.

giacomo16v 24th Mar 2020 5:06 pm

Re: Philips SBC850 Multimeter
Unfortunately, the knob attached to the black variable resistance is attached very strongly and I would like to avoid forcibly detaching it, in order not to compromise the aesthetics of the multimeter, which could be damaged by tele operation.

Station X 24th Mar 2020 5:15 pm

Re: Philips SBC850 Multimeter
I'll leave it to someone with a better value of resistor colour codes than me to determine the values.

Have you determined which ranges work and which ranges don't? With this information it might be possible to determine whether the burned resistor is a multiplier resistor associated with a voltage range, a shunt resistor associated with a current range, or a resistor associated with a resistance range.

Knowing the values of the other resistors associated with the faulty circuit function may enable the value of the burned resistor to be calculated.

Does the meter scale plate give any indication of Full Scale Deflection (FSD) current and internal resistance?

What ranges does the meter have? The same as in post #3?

giacomo16v 24th Mar 2020 5:25 pm

Re: Philips SBC850 Multimeter
To do this I would have to remove the pcb from the plastic container and unfortunately it is very difficult as the knob attached to the black variable resistance is attached very firmly and I risk damaging the outside of the multimeter. Crowella, by chance, can you disassemble the pcb and send us a photo of the electrical tracks?

giacomo16v 24th Mar 2020 5:51 pm

Re: Philips SBC850 Multimeter
yes my multimeter is the same of the post #3

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