Pioneer SX-770 find

Kingfisher

Well-Known Member
Recently bought one of these from a thrift shop for $21. Sounds great and looks great except for the fact that half the panel lights are burned out. Anyone know where I can get replacements? 3 of the four fuse-type "festoon" (8v 300mA) bulbs are out and the "bayonet" bulb behind the tuning meter (8v 250mA) is out as well.

One other question: The voltage selector on the back is set to 117v but the voltage in my house is around 122-123v, would it be better to change the voltage selector on the Pioneer to 130V, or would that not be enough to power it properly?
 
For cheap, you can get replacement festoon bulbs at your local auto parts store. Just take one bulb with you to compare the size. If you really want to jazz up the 770, get some LED festoon bulbs. You can find a suitable replacement bayonet bulb at your local Radio Shack, just take the bulb with you to compare.

As for the voltage selector, mine is set to 110. I am getting 122-123 at the outlet. My 770 is over 40 years old and still going strong. It has been set to 110 all its life. I would say leave it set at 117 and enjoy it.
 
For cheap, you can get replacement festoon bulbs at your local auto parts store. Just take one bulb with you to compare the size. If you really want to jazz up the 770, get some LED festoon bulbs. You can find a suitable replacement bayonet bulb at your local Radio Shack, just take the bulb with you to compare.

As for the voltage selector, mine is set to 110. I am getting 122-123 at the outlet. My 770 is over 40 years old and still going strong. It has been set to 110 all its life. I would say leave it set at 117 and enjoy it.

Mine was built in Mar. 1971
I tried Rat Shack for the bayonet bulb, but all they have is a 6.3v 250mA bulb (commonly referred to as #44). Won't the socket apply excessive voltage since the original was 8 volts?
 
I have two of those 6.3v bulbs in my 770. Been in for about a year now. No issues yet of bulb burnout. They work well and I cant tell a difference between them and the original 8v bulbs still inside it. If you really want the 8v bulbs, I suppose you could locate some if you look hard enough.

My 770 was made Jan. 1971. On a side note, I am guessing that you have already given every pot and switch a thorough deoxit bath. I really hope that yours came with the speaker plugs. If it did, that is truly a nice score. Get her cleaned up and fix those lights and you will really enjoy the 770. It has a really nice sound. She puts out about 15 wpc at 8 ohms, but she will give any set of speakers a good workout with a turn of the volume knob.
 
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Hi, Kingfisher! New to AK, but long time reader. I just picked up a SX-770 today that I'm cleaning up. The bayonet bulbs are all working fine. None of the festoon style behind the face plate work. One appears to be missing all together.
Two questions if you read this:
1.) are these bulbs wired in series where if one is missing, they all go out? I have an old technics like that.
2.) did you find any good replacements? LEDs would be nice.

Thanks in advance for any advice/tips.

Now to find/make some of those stupid speaker plugs...
 
1. not series wired. but there is a fuse, however if the bayonet bulbs are working, they are on the same fuse.
2. the usual 7.5v AC power runs them, check eBay. plenty of choices there nowadays.

Check the speaker plug thread, plenty of improvised plug tips in it.
 
1. not series wired. but there is a fuse, however if the bayonet bulbs are working, they are on the same fuse.
2. the usual 7.5v AC power runs them, check eBay. plenty of choices there nowadays..

Check the speaker plug thread, plenty of improvised plug tips in it.

Thanks for the tips. Good to know how the bulbs are wired. Found some 8v LED festoon type lamps on eBay in blue. Ordered 5.

Saw the threads on the improvised speaker plugs. Super helpful. Seems like there are lots of ways to rig up the speaker connections.
 
chris35745 & Kingfisher. (also via reno) If your 770 is Multi-Voltage, You should set your voltage selector to a voltage that is higher than your wall voltage. Setting it for 110 or 117 and having a wall voltage of 120v-125v is potentially overloading the windings on the transformer (heating it up more than it should be due to less winding being used for 110v or 117v). Set it to 130v, and the full primary winding will be used which will help with cooling the transformer, AND help stabilize your voltages when occasionally cranking to 11. Plus with a less strained power supply, the voltages will be more in line with what is required, and the sound will be improved.

This is for the 727 but it would also apply to the 770 with multiple voltage transformer. Use the Fuse ratings on the 770's back panel.

ScreenHunter_46 May. 25 13.33.jpg
 
chris35745 & Kingfisher. (also via reno) If your 770 is Multi-Voltage, You should set your voltage selector to a voltage that is higher than your wall voltage. Setting it for 110 or 117 and having a wall voltage of 120v-125v is potentially overloading the windings on the transformer (heating it up more than it should be due to less winding being used for 110v or 117v). Set it to 130v, and the full primary winding will be used which will help with cooling the transformer, AND help stabilize your voltages when occasionally cranking to 11. Plus with a less strained power supply, the voltages will be more in line with what is required, and the sound will be improved.

This is for the 727 but it would also apply to the 770 with multiple voltage transformer. Use the Fuse ratings on the 770's back panel.

View attachment 937277

Thanks for the info! I will look into this for sure.
 
It's a great sounding receiver!!
 

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So, got this 770 up and running. A thorough cleaning of the face plate, knobs, and insides. Deoxit on all the switches. Two coats of tung oil on the wood case. New blue LEDs for the backing lights. Just sat down and listened for the first time. HOLY CRAP. Ear-gasms. Not to mention it now looks brand new. Will post pics later.
 
Never had a 770, but have 2 1500TD's which was the TOL of that series. An under the radar series all with cap coupled tube like warmth! Enjoy!
 
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