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Need to find where i can get a ceramic cement resistor or equivalent please. The white 2W 3ohm 3K in photo

Texscowboy

Dec 20, 2023
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Digikey, Mouser for a couple.
Thanks, I'm a newb at this so when i searched the places i don't get anything that remotely looks like the one at all. So not sure as to what would replace it as an equal. Thanks
 

73's de Edd

Aug 21, 2015
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With that 3K tacked on the end , but with no intermediate R inserted . . .its a puzzler.
If the unit tests as open with an ohmmeter connected to each leads.
Then try this . . .
Use a jumper clip or bared wire to connect both end resistor leads together and that will be 1 connection to an ohmmeter lead and then you get a single edge razor blade which is quite beefy and its aliminuminini- yum- yum band across the top side, which you press and hold the other ohmmeter lead FIRMLY against . . . . to make connection. The ohmmeter is initially in the continuity "BEEP" position. Go to dead center of the back side that has a hard plaster of Paris type of filler.
Initially touch blade to either end wire and expect a BEEP.
Then, start digging in with a rotary drilling action with a corner of that blade.
You are expecting, after going down a bit, to touch contact with a good portion of that coiled resistance wire . . . . and a BEEP upon making contact with it.
Then switch to ohms range and test again when repeated contact is made with the exposed connection in that cavity. Then see what the resistance reading is and double its value of resistance .
If not finding contact, shift to digging holes at 1/4 from ends positions and computing as 4X the readings.

I'm wanting / highly expecting to see that be a 3 ohm value.
 

Delta Prime

Jul 29, 2020
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Madisound 3.0 Ohm, 5 Watt Wirewound Resistor
5 watt cement resistor
1703071997973.png
Tolerance: 5%
Tinned copper leads: 29mm + 3mm long
Dimensions: 10mm H x 10mm W x 22mm L
Flame proof ceramic case with flame proof cement
Ceramic core
Press fitted end cap
The alphabetic code F,G,J,K,M
Is the resistance tolerance given in percentages plus or minus the nominal resistance F=1%, G=2%, J=5%, K=10%, M=20%.
I couldn't find a 2watt, 10% resistor.
So this is an equivalent, higher wattage and better tolerance.
Same omic value.
 

Minder

Apr 24, 2015
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Thanks, I'm a newb at this so when i searched the places i don't get anything that remotely looks like the one at all. So not sure as to what would replace it as an equal. Thanks
Digikey have a few, this one for example exact value.

CB5JB5R00
 

73's de Edd

Aug 21, 2015
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Sir Texascowboy . . . . . . . . ("Here We Go!" )

THINK ABOUT THIS NOW . . . . . .

We see the . . .erCAP
ker V1
Circuit board, which we are to assume that initially rated 2 watt wire wound resistor come from . . . . and you never did definitively say if the resistor unit went . . .belly up . . . open circuit. ? ? ?
Also visible us an upper mammoth E-cap and an adjunct " SOLAR" connector (pin sized. for NOT a sizeable amount of current capability ).
Matter of fact, the slide switch located lower down is current rated higher than that just mentioned connector.
Then there is that next connector that width and end shapes, no what near a mini USB or that family of connectors.
Then there is the very bottom black push button? / switch? / connector?

Now an analysis . . . . .
If the original resistor failed / by open circuit . . . . . .likely by some serious overload subjection . . . . .
1 . . . . .Consider a RARE possibility of internal loss of resistance wire element end to wire lead bond.(Manufacturer defect)
2 . . . . . Power over consumption of that resistor over a time period, results in its going open circuit . . . . . .fortunately that is accompanying with a clue by, with a cumulative darkening of the cermet central potting compounds surround.
3 . . . . . That resistor was just FLAT overloaded, and a resultant opening up.

If being the last possibility was the situation . . . . . . consider that a 2 watt rated unit would run" forever" at that / its rate of power dissipation.
Have 3 watts running thru it . . . . . and your finger touching it tells you that it can feel it.
At 4 watts thru it . . . . .your finger says . . . . .that thing is getting W . A . R . M
At 5-6 watts thru it . . . . .your finger says . . . .that thing is getting HOT. . . . . . resistor eventually opens up.

NOW what if circuit design intent was for that 2 Watt marginal rating to serve as a protective fusible resistor (sacrificial / blow-up-able on overload) for its connected circuitry.
If such was the case, your changing to a 5 watt rating would end up in a FIERCE current passage before effectation.

SUGGESTION . . . .
Upon installation of that new resistor it might just overload on powering up.
With a new 3.3ohm value . . .you decided upon . . . . at higher wattage . . . . . initially take a voltage reading across that resistor in DC (and then also do AC) meter voltage function, to see what voltage is being read across it .
So initially, have metering clipped across that new resistor to see if greater than 6.6 VDC reads across it . . . . .initially meeting the initial 2 watt specs.
If perchance, greater than 16.5 VDC . . . . . . meeting your new resistors run spec . . . . .shut power down. . . . .investigate.

If the unit runs at below those spec limits . . .ADDITIONALLY . . . . test at ALL other modes of operation that might be pulling much more power thru it.

That's the best that I can do, with our not even knowing equipment function and circuitry / schematic assist

73's de Edd

Some people elate happiness wherever they go . . . . . . .
with others . . . . . its whenever they finally go.


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