Is this the wrong resistor installed on my new CR-1020?

[stevepe]

Thx Steve ! Do you have a link of this component ? I'll try it too.

I mistook this post for another one a while back. Sorry. If you are replacing the fusistor shown in the photograph at the beginning, it is supposed to be a 10 ohm. The one I found in there was wrong.

There are some other 10 ohm resistors shown in 4seat pilot's photo, and they take more current than the one I think you mean. Merrylander recommended 3 watt for those down near the 22ohm resistors.

Ohms law says 1/2 watt, but I used a 2 watt since 1/2 watt wasn't confirmed by an expert, and the higher wattage replacements are definitely recommended for others on this board.

Here is what I used:
http://ca.mouser.com/ProductDetail/Vishay-BC-Components/PR02000201009JR500/?qs=sGAEpiMZZMu61qfTUdNhG0tB2PVrvXU89p%252bE5LRTizA%3d

 

[4seatPilot]

For the specific resistor in question here, which is the single one in the top center of the cap board, a 1/2 watt is specified - if it over-currents for any reason, it will fail and hopefully protect downstream components. The other 4 resistors (2 red ones, and 2 fusistors) do need to be upgraded in wattage (3w for the 1020, 3.25w for the 2020). The originals in the 2020 were only 2w, so got way too hot and caused physical damage. The 1020 doesn't have quite as severe a problem, but upgrading those isn't a bad idea. The rest of the fusistors (including the focus of this thread) should probably be left at stock watt values... so 1/2 watt here.

this would work fine

 

[echkos]

So if I got my maths right, with a 24 v power supply I should use a 5.3 Watt resistor for a 220 mA current ?

If there's too much current for any reason the resistor will break
and stop the continuity ?

Thanks for the info !

For the specific resistor in question here, which is the single one in the top center of the cap board, a 1/2 watt is specified - if it over-currents for any reason, it will fail and hopefully protect downstream components. The other 4 resistors (2 red ones, and 2 fusistors) do need to be upgraded in wattage (3w for the 1020, 3.25w for the 2020). The originals in the 2020 were only 2w, so got way too hot and caused physical damage. The 1020 doesn't have quite as severe a problem, but upgrading those isn't a bad idea. The rest of the fusistors (including the focus of this thread) should probably be left at stock watt values... so 1/2 watt here.

this would work fine

 

[4seatPilot]

So if I got my maths right, with a 24 v power supply I should use a 5.3 Watt resistor for a 220 mA current ?

If there's too much current for any reason the resistor will break
and stop the continuity ?

Thanks for the info !

If what you are trying to accomplish is passing 220mA at 24v, correct. A 110ohm resistor, with 24v across it, will pass 220ma and dissipate 5.3w. But this is not what you are looking for here. A 5w resistor is going to be very large, and will not protect anything in this position. The schematic specifies a certain resistance, capable of passing a certain amount of current because it is referring to a fusistor. So you use the resistance and the current to calculate the wattage. 10ohm, capable of passing 220mA without overheating, requires a .484w (1/2w) resistor.

 

[echkos]

Ok , thank you for your help ! I'll get some of
those resistors and let you know how it worked.

If what you are trying to accomplish is passing 220mA at 24v, correct. A 110ohm resistor, with 24v across it, will pass 220ma and dissipate 5.3w. But this is not what you are looking for here. A 5w resistor is going to be very large, and will not protect anything in this position. The schematic specifies a certain resistance, capable of passing a certain amount of current because it is referring to a fusistor. So you use the resistance and the current to calculate the wattage. 10ohm, capable of passing 220mA without overheating, requires a .484w (1/2w) resistor.

 

[echkos]

Worked well

Hi guys,

Just wanted to let you know that the replacement went
really smooth and everything work as it should.

Thanks again for the support!

 

[stevepe]

Congratulations!

 

[sonnyboy65]

Avionic's note mentioned above

Here's a picture of the correct orientation. (I'm not 100% sure, but I think the "+" was in the correct location on this board (in The Fez's 2020). The problem is I think the + that is to indicate polarity of the big reserve cap... but it looks like it's for the smaller one nearby.

The reason for changing resistors is quite evident as well.

Well this explains a lot!
Going way back in the forum but I'm looking for clarity on this capacitor orientation. Is the photo in fact correct?
When I bought the cr-1020 it wasn't working "it has a hum" and I found this capacitor to be missing from the board and rolling around inside the unit so I haven't plugged it in. The board marking is different from the schematic.
There are a number of other janky looking things done to this board, diodes soldered to resistors, a "recap" that may have been done with a blow torch and some trace patches. It's also possible it may have been on fire at some point as there are some blackish patches so a backward capacitor wouldn't surprise me at all.
The service manual available online is quite difficult to read, as you've surely noticed.
I'm only $50 into it but it's quickly becoming personal and I really appreciate the advice I've found here.
Thank you all!