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

stevepe

stevepe

Active Member
The fusistor that says HW20410 under it on the board has obviously been replaced, and is .47 ohms. Isn't this supposed to be 10 ohms in this spot? Seems strange. On the schematic, the one I think it is is right next to C813 (the orange one 100uf). I think it has to be FR803 Bottom left in the photo.

Screenshot2013-01-09at45902PM_zps53b53b1c.png


IMG_9108_zpsf1d70cf3.jpg


This receiver seems to work well. Replaced outputs and this resistor are the only signs of the work the PO had done when a channel went out. I'm reading up on the service bulletin stuff to replace the cap board's 22 and 10ohm fusitstors and resistors respectively. I'm getting some much appreciated tips from 4seatPilot as well.

Thanks,
Steve
 
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Looks like its suppose to be a 10Ω than that .47Ω. FR803
 
I just looked at my 2020 and it has a HW20410 (10Ω) resistor installed in that position.
 
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10 ohm

All you can do is replace with a 10 ohm.
See what happens.
If there is a problem and it blows, you have another project.
What made the 10 ohm blow?

Paul
 
That is the one we discussed on the phone, yes? I'll double check my 1020 tonight, but pretty sure it was a 10 ohm...

Those apparently will fail as a matter of course - don't need a cause. just being an old fusistor is enough I guess.

Sent from my GT-I9100 using Tapatalk 2
 
Well, it's completely confirmed that it's 10 ohm, and it's the one I asked about on the phone. This was how it was when I bought the receiver not too long ago.

So, 1/2 watt 10ohm replacement? .484 watts is the value i get with the Ohm's law equation (.220A squared x resistance.) I replaced the fusistors in my CR820 with 1/2 watt. – .085A 68ohm = .49 watts

I ask, because it may not apply to some of these metal film (flameproof) resistors that are to replace fusistors. Merrylander recommended 3 watts for the 22ohm and the 10ohm's in line with them to be replaced on this same board. (BTW, the two other 10 ohm resistors say 33 ohms incorrectly in the schematic.)

It seems like they should be as low of wattage as will hold in normal use if they are to give protection. I know enough not to contradict what Merrylander says, but can someone explain? Is it because they are arranged a certain way?

Thanks Everyone,
Steve
 
There was some confusion regarding Yamaha schematicts as the CR-1020 and CR-2020 used the same design and circuit boards, so the 3 watt resistors should be 10 ohms on the 1020 and 33 ohms on the 2020.

If you look at the head amp section of a 1020 you will see all the empty spaces for the MC pickup head amp for example.
 
I didn't realize the 1020 and 2020 were so remarkably similar till 4seatPilot pointed it out to me. He made me buy this one. :D

I'd seen Merrylander's correction of another poster's confusion about 33 vs 10 ohms. I just thought the other guy misidentified it or something, not that it was labeled that way for the big brother. It takes "no user serviceable parts inside" to another level! Avionic's handy hint about a mislabeled board- (+/-) reversed for a cap on this same board applies, as well. I'm not sure this goes for the 1020, but I'll really scrutinize the orientation for the new caps.

It may not be worth going into for the likes of me, (a novice in electronics theory), but I'm still curious about how optimal wattage is determined for fusistor replacement. I think I remember Fred Longworth saying that it's more critical than the type of resistor.

Thanks,
Steve
 
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.
 

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I'll check my 1020's board. IIRC, the + is in an ambiguous place. The two photos do clearly show an opposite orientation on the installed caps.

That 10 ohm 220ma fusistor on top of yours is labeled quite differently on mine. Mine has hw-20410, instead. Are you going to replace that too? You hate fusistors plenty. Merrylander seems to want to leave well enough alone if they are in a place that doesn't have a lot of current- such as the the one on top, and the ones on bottom of the L. and R. amp boards. (100ma 68 ohm)

I also need to replace a little ceramic disk cap (.01ohm 500v?)) next to one of the 10 ohm resistors. It's coming apart- from heat, I presume. I don't see it in your photo, though.

I'm looking into some beefier heat sinks for those 234's, too. Not a lot of room, though. Even in the 1020 the grate on the case is smoked a bit. Not uncommon, I gather. No way I can keep my finger on them. I could make some out of copper.

Steve
 
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hello Avionic and stevepe

Fuses resistors are identical for all countries but yamaha part numbers are a little bit different
In this case european " FR803 " is Yamaha part number HW104100 same fusing resistor for US market is HW204100
I have the pleasure to offer you all my list (home made) for most used fusing resistors in old YAMAHA units !
Let me know your point of view !
:banana:
clinic-audio
 
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Nice info!

So some boards are printed with the part number, some with the resistor values. Interesting.

Sent from my GT-I9100 using Tapatalk 2
 
Yes, thank you for sharing your list with us. It gives me a broader perspective on the problematic value-changing fusistor/fusing resistor. Seeing a long list makes them seem more manageable, somehow. In my head, anyway.

How do you go about choosing replacements, if you don't mind my asking?

I realized that there is an extra zero at the end of all the entries on the list, compared to what I' seeing, besides the 2 and 1 difference at the beginning. It's clear, now.

Thanks,
Steve
 
yes , stevepe

All the old spares part numbers are with 2 letters (HW for exemple ) and always 6 numbers ( like 204100 )
Now, you know that, if you read some part number inside service manual with HW20410 the right one is HW204100
This is true untill year 2000 ( I think ) because they more caracters after , too much spare parts !
Have a nice day !:banana:
 
hi all,

did anybody found a replacement for this fusistor ?

i'm trying to replace some of them but cant find them anywhere..

thx !
 
Ah-ha! There's that list I was looking for... I knew someone had posted it, but couldn't recall where. Board has the part number printed on it, schematic has the values... here we have both. :thmbsp:

As for replacement, I've been just using metal film of equal ohm & wattage. (calculate watts using ohms law and the values of the fusistor)
 
4seatPilot said:
Ah-ha! There's that list I was looking for... I knew someone had posted it, but couldn't recall where. Board has the part number printed on it, schematic has the values... here we have both. :thmbsp:

As for replacement, I've been just using metal film of equal ohm & wattage. (calculate watts using ohms law and the values of the fusistor)
Click to expand...

Hi 4seatPilot,

Thanks ! But is a metal film a simple resistor ? or is it a fused one ?
 
echkos said:
Hi 4seatPilot,

Thanks ! But is a metal film a simple resistor ? or is it a fused one ?
Click to expand...

I used a metal film. I think this is standard procedure. IIRC, it was 68ohm 1/2watt. You won't find a fusistor like the original, and you don't want one.

Steve
 
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