Re: RCA RT2770 Reciever (Home Theater?) Need help!
All,
I reached out to RCA support on this. Got a response, but they are still looking up the values by schematic spec.
Will let you all know what this are and what I recommend for replacement.
Since I repaired switching power supplies for 2 years, back in mid 90's, hope you found my inputs helpful.
Snubber network failures made up over 70% of all failures in these switched PS units, so really know this scenario well.
Cheers!
OMR
OldManRiver
New Member
Last Activity: 10-28-2013, 11:14 AM
Joined: 10-17-2013
Location: Garland, TX
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Re: RCA RT2770 Reciever (Home Theater?) Need help!
WP,
Wow no wonder C211 is blowing. This has to be rated well above 20K volts.
I typically use 35-50KV caps on these ckts as the voltage spikes from the XFMR inductance loading is always over 20KV, usuall over 30KV.
Cheers!
OMR...Leave a comment:
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Re: RCA RT2770 Reciever (Home Theater?) Need help!
tom66,
This is a "snubber network" C211 and R202, so only handles or "clamps" the high voltage spikes produced by inductance rings (by loading) on XFMR T103, when power switching MOSFET V103 switches on. Therefore it is only there, C211 calculated for resonance of frequency to kill/clamp all spikes exceeding the voltage rating of fast response dual diode stack D207, as fail safe to not compromise it. These spikes, can only be seen on scope with high voltage probe, exceed 20K volts,...Last edited by OldManRiver; 10-17-2013, 03:55 PM.Leave a comment:
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Re: RCA RT2770 Reciever (Home Theater?) Need help!
Wolf_Punch,
Per other entries and pix this would be 8.7 - 190 ohm, but betting on 10 ohm 1 Watt 5% resistor. Also from your comment and others looks like RCA engineering, not understanding the problem of the under rated voltage on C211 has upped the wattage on this resister to 5Watt, but not necessary if C211 is replaced with new cap, same mfd rating, but 35-50 KVAC rating.
Cheers!
OMR...Leave a comment:
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Re: RCA RT2770 Reciever (Home Theater?) Need help!
HCC,
If there is no white band then this is 10 ohm 1 Watt resistor.
Cheers!
OMR...Leave a comment:
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Re: RCA RT2770 Reciever (Home Theater?) Need help!
siski123,
Please post pix of your unit and show the Model # of the PWR brd as there are several version of this brd out there and seems RCA engineering is beefing up this snubber network, but uping value on R202 is not the fix, it is the voltage rating of C211 that needs upping!
Cheers!
OMR...Leave a comment:
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Re: RCA RT2770 Reciever (Home Theater?) Need help!
siski123,
My model PWR brd (MAR/23/2007) the resister is film type like pix shown and is a 1W resister. However it is not the resister that is the problem. It burns only when C211 shorts, under high voltage. Spikes on this exceed 30KVAC.
You have to replace the cap or resister will continue to burn out.
Cheers!
OMR...Leave a comment:
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Re: RCA RT2770 Reciever (Home Theater?) Need help!
HCC,
I'm not sure of the color bands I'm seeing here. Is it Brown, white, black, gold? Gold is the tolerance percent rating (5% for Gold) and always must be the 4th band, so what is it.
If it is Brown, white, black, gold then value is 190 ohms, which should be right for this "snubber network".
For more info on this ckt and snubber networks, see my thread at:
[url]http://www.hometheatershack.com/forums/diy-repair-maintenance/70387-rca-rt2770-r202-c211-power-supply.html[/url]...Leave a comment:
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