Picked up an SX-737 today

[Eastham]

Won the auction at £55 and picked it up today, kinda dirty and the controls needed some cleaner.

Before:

After:

('scuse the mess in the background..)

All the lamps apart from the dial pointer lamp are working suprisingly. DC offset measured at 7mV right and 2mV left, both adjusted to 0 and idle current was perfect. The flip switch knob for the power switch has been replaced with a non original one so I guess I'll have to source one. I also accidently snapped the dail pointer while removing the diffuser, I managed to glue it back together but it still kinda bums me out something else to look out for. I am having an issue with the speaker relay not making good contact aswell, I've tried cleaning it but it's still a bit iffy, is there any kind of replacement out there any one could suggest? I also noticed an error in the Service manual It says to adjust VR1 and 2 for DC offset but from what I can tell from looking at the schematic they adjust the Bias and VR 3 and 4 adjust offset, it's not like Pioneer to make a mistake like that.

As for my thoughts on the sound. I love my Sherwood and how detailed it is but this SX-737 blows it out of the water despite having half the power, compared to the gear I had in the past my Sherwood had much more detail in the bass and highs, fast paced drum beats and cymbal crashes sounded more realistic and pronounced but holy crap, this 737 took those details and turned it to 11! And it's noticeably brighter. Needless to say I'll be performing a recap on this unit!

 

[Eastham]

Well I fixed my relay, here's how I did it.

First a before pic, look at all that lovely pitting on those contacts.

First I carefully bent the rest contacts back so I could fit a Q-tip in between the contacts.

I then applied some metal polish to the Q-tip and polished all the contacts 'till clean and used another clean Q-tip to buff the residue off.

All lovely and shiny.

Then bend the rest contacts back into place and enjoy your stereo with no more channels dropping out.

 

[loweran]

Love my 737. You will too! Looks like yours is in great shape. You going to recap it?

 

[Eastham]

Love my 737. You will too! Looks like yours is in great shape. You going to recap it?

It certainly cleaned up nicely but somehow the chassis has bent in the middle so I'll be figuring out a way to fix that next. It's looking more and more likely I'm going to recap it, it's a very nice receiver and well worth it to me.

 

[gizzyman47]

I bought one a while back. I remember it sounding pleasent to me.

 

[432HzBob]

Pioneer black-face, blue light units, 1974-1976?, sound great to me too.
I have a 828 in the closet needing some new caps and PS relay but someday it will work again.
PS: be careful with 4 Ohm Infinity speakers. My RS-6's cashed 3 SX receivers

 

[Eastham]

Pioneer black-face, blue light units, 1974-1976?, sound great to me too.
I have a 828 in the closet needing some new caps and PS relay but someday it will work again.
PS: be careful with 4 Ohm Infinity speakers. My RS-6's cashed 3 SX receivers

Hmm, don't think I'll have to worry about that for a while, Infinity speakers are a little out of my price range for now.

Another little update. I cleaned out the insides as best I could with a brush and Isopropyl on a rag, smells a little less like nicotine and old people now. I also managed to bend the chassis back straight again which was pretty easy, the metal is pretty thin and is easy to manipulate with your hands a hammer and a block of wood. And finally I gave the vinyl case a quick polish and it came up pretty nice.

 

[432HzBob]

You will love it!!

 

[Oldsansui441]

Nice 737 you have there, great job on the cleaning. l had one a while back and liked it also, still have my 939 though. Yes you are correct the service manual is incorrect in regards to which trim pots for bias/dc offset, they are reversed as you mention. The dial pointer uses a grain of wheat globe, 8v from memory. All the best with your new purchase.

 

[Eastham]

Nice 737 you have there, great job on the cleaning. l had one a while back and liked it also, still have my 939 though. Yes you are correct the service manual is incorrect in regards to which trim pots for bias/dc offset, they are reversed as you mention. The dial pointer uses a grain of wheat globe, 8v from memory. All the best with your new purchase.

Strange little oddity in the service manual for sure, the dial pointer lamp seems to be a 3mm 8v 50ma I think.

 

[Oldsansui441]

Strange little oddity in the service manual for sure, the dial pointer lamp seems to be a 3mm 8v 50ma I think

Yes it is strange. That globe sounds right.