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I have a dead Ohm meter... for JVC RC M90

bredgeo - 2009-11-14 02:58

Hello...... I need help with a resistor in a RC M90!!!!!!!

This one:







I guess you GOT THE PICTURE..... Laugh Out Loud Laugh Out Loud Laugh Out Loud Laugh Out Loud

Hum, Hum.... Well, all my tools are in France so I was only able to use my small handy pocket ohm meter... And I get "No Resistance":



Help!!!!!!!

And, tank ya vary mush!

Humble Brian... Roll Eyes

kittmaster - 2009-11-14 06:27

that isn't no resistance, that is zero ohms, which means it is shorted or directly connected from one point to another.

bredgeo - 2009-11-14 07:33

Hey Kit.

Not a resistor you say.... hummm...

I unsoldered it before taking its value. So your are saying it is not a resistor... Do you have a tech. manual saying what it is for there is two tons of glue that I do not want to undo (for mine is still working well) to see what ever colour codes and info marked on the circuit board.

Let me know if you have the value -of what it is- etc.

Later

drmr2000 - 2009-11-14 08:35

I would desolder that resistor then check the ohm's 0 Ω, means dead short, see if it measure the same, could be bad capacitor or regulator on that cicuit, causing the short circuit. That resistor does look burned, could be the glue?

bredgeo - 2009-11-14 10:32

Already did that.... i un soldered it before take the value. I do not think it is burnt... What we see is glue.

One thing I can say, Pascal who is having the problem, had no motion in the tape mech of the M90 with his being burnt out. So he replaced mit with a temp resistor and it works.

What he wants is to know the correct value of that resistor, and asked me to check. beingthat my M90 work corectly... I am guessing that that resistor is not burnt out, but my little meter is.
That is why I asked for help (I do not have a tech manual for the M90)

Later

drmr2000 - 2009-11-14 10:55

Have to look at the service manuel when I am off, there sure be color strip on that resistor, if tell us what the colors are on that resistor in order, then can tell you how many ohms it is.

bredgeo - 2009-11-14 11:09

Oh..... I would have done that myself... But you know how chaos is the only constant in the univers!

There is two tons off glue over it, and I do not want to try and remove it... after 25/30 years... it could break up into pieces!!!!

So, if you guys have a tech manual... they will probably have its value in it, and we are home free!

Merci!!!!!!!!!

transwave5000 - 2009-11-14 15:37

Its probably a fuse-resistor.
Actually a fuse that looks like a resistor.

FR704 part.
FR = fuse-resistor

superduper - 2009-11-14 19:52

Bredgeo. I already responded in the other forum. FR704 = 4.7ohms, 1/2 watt fusible resistor. Primary function is most likely to protect the circuit. If your buddy replaced the resistor with a standard resistor, it will work BUT you'll lose fuse function. Don't recommend operating it in that manner, especially since it blew once before. Could be trouble in the making.

transwave5000 - 2009-11-14 22:38

If a 1/8 watt resistor is used you can still get
some fuse function as than
the resistor will open or burn up.

Loooks as if there is still voltage
on the circuit board from ohm meter.

bredgeo - 2009-11-14 23:25

All the info is given to him for the M90 to be fixed...

I had a look on the net to see if I could find an FR 704. But I did not find a 704 (but a lot of others that seem to fit the needs...???

If not, the FR in the pics I posted was un soldered and the M(0 not plugged in... That is why I think my little ohm meter is dead. Frown

superduper - 2009-11-20 00:09

Bredgeo. You are not going to find a FR704. The reason why is because that is an arbitrary number assigned to that resistor by JVC to enumerate in their parts list. In other words, if JVC has a device with 4 fusible resistors in their parts list, they will likely enumerate them FR701, FR702, FR703, FR704, etc. The 7 probably refers to the circuit board #7. You will also find that the capacitors on the same circuit board are enumerated similarly, such as C701, C702, C703, etc. It has nothing to do with the value of the part -- only the part reference number for their service manual and parts reference. So if you look at the parts list on the service manual, you will see that FR704 refers to a 4.7ohm 1/2 watt fusible resistor.

Therefore, IF you search for 4.7 ohms, fusible resistor at 1/2 watt, instead of FR704, guess what? NO more trouble finding parts !

As for the ohmmeter -- I'm not sure I understand what you are saying but usually on analog type meters, you zero the meter by touching the two leads together with the meter set to the resistance test function, then turn the little screw in the center of the meter until it reads zero. Then test the part.

bredgeo - 2009-11-20 03:41

Hummmmm....... Very good!!!!!!!!!

So all is clearer than clear now.

If not, I have zeroed the meter since last I posted, but have not reopened the M90 to retest... well, with all this info I do not think I need to any more!

Thanks for all that

stynger007 - 2009-11-25 06:34

Just went through this, used this program Resistor value finder to match the resistor values, as a previous poster said the JVC codes are proprietary. I use a digital meter and depending on the resistor I use the 20k, 200k, 2000k settings, works like a charm.

Good luck to you

bredgeo - 2009-11-25 10:15

Mercy, mercy buckets! Big Grin