QRX-7001 lights

[n8nagel]

Well, I received today via eBay and the Brown Santa a Sansui QRX-7001... amazingly enough it looks just as good as it did in the pictures, and I had no issues whatsoever with it save for an initially dead right channel that was sorted by working all of the switches around. All inputs work, and it sounds pretty good. This is intended to be the basis of a bedroom "vintage surround" system using an Oppo BDP-103 to downmix modern digital sources to 4.0. the only thing I have not been able to test is the CD-4 demodulator as I haven't quite got the hardware together for that, but it'll do for the intended purpose.

Only other issues:

1) the "4" does not light up in quad mode. the "2" does in 2-channel. I'm assuming this is just a light bulb with fiber optics?

2) the left end of the dial is dimmer than the rest of it. I remember reading something about some resistors needing to be replaced along with the bulbs to make the dial lighting even but I can't remember details or where I read it. anyone help?

Specs on light bulbs if you have them would be appreciated, I have not yet reached out to dgwojo who is my usual go to for things like this.

Can't wait to get this set up, I put a modern AVR in the bedroom for a while (shaking it down before giving it to a friend's dad) and SWMBO likes having surround in there (4.0 as that's all the room there is for speakers) this will do all that that does plus play quad LP formats and it's cool looking and vintage so this makes me very very happy! she may miss the volume control though... But on the upside the receiver on this one works; the couple year old Denon AVR only has an FM tuner and it crapped out after about two days of use, waiting for replacement parts... guess score one for old school Sansui (and I like listening to NPR on Saturday mornings while drinking coffee and reading in bed, this fits my lifestyle much better)

 

[n8nagel]

followup:

Before I tear this thing apart and start measuring stuff has anyone done this dance before?

looking at page 26 of the SM "Other Parts - Front Side"

the two meter lamps #15 P/N 0420040 Fuse Type Lamp 7V 300mA

the function lamps are #19-22 P/N 0400340 Lead Type Lamp 7V 100mA for FM STEREO, HALL, SURROUND, QS, SQ

the odd one is the #23 CD-4 lamp P/N 0400390 Lead Type Lamp 6V 30mA

it appears that there are four fuse lamps behind the tuning dial, #25 but the parts list does not list them

it also appears that #29 "Digital Indicator" was intended to be sold as a unit, it appears that it has three bulbs, one for the backlight, one for the "2" and one for the "4".

Of course, the bulbs I *need* are apparently 2 of 4 of the tuning dial fuse lamps and the one for the "4" in the "Digital Indicator."

It looks like unless I can find a really short right angle screwdriver the face will have to come off to inspect these bulbs, so before I go to that trouble I figured I would ask here and see if anyone's done this dance before and if so what they ended up using. I'm not completely opposed to using LEDs either if these are fed by DC (have not even measured yet) as long as I can maintain a relatively stock-ish appearance. I'd rather not do that because I also want to start using it as the AVR in the bedroom has a dead tuner (parts on backorder) and I really miss listening to the radio on weekend mornings.

 

[n8nagel]

OK, all the dial lamps are the exact same as the meter lamps marked "STANLEY 7V 0.3A" 1/4"x1.167" guess that would be a 30mm fuse lamp?

the function lamps are all 4mm bulbs but have a little plastic sleeve on them to make them about 4.75mm where they fit into their holders

The backlight for the digital indicator is a 4mm bulb wit ha metal sleeve on it; the sleeve is about 7.5mm diameter (.298") marked "STANLEY 7V 0.1A"

still trying to figure out the "2" and "4" lamps they are 3mm bulbs with a little heat shrink on them to fatten them up where they go in their holders, but I measured the working one at 8.2 ohms so that can't be right. Guess I will have to unsolder one leg and measure current in operation...

 

[n8nagel]

they're drawing about 75mA. Just measured the "2" today. dgwojo is the man, I'm going to replace the "2" and "4" with incans but he had LEDs that would work for the "digital indicator" backlight which failed at some point while I was poking around and I'm going to replace all the fuse lamps with his LEDs while I'm in there because it's such a PITA to get to them and they look like they're cooking everything around them. I reached out to him this afternoon once I'd measured the still working "2" lamp and he managed to get what I needed in a box and out the door in literally minutes so I should have them Tuesday. I can't wait to try my "vintage surround" system in the bedroom

 

[n8nagel]

Follow up:

When I went to actually do the work I removed all the old solder on the fuse lamp holders on the dial backlight assembly and resoldered them. This actually made everything work with the old incandescents but I went ahead and put the LED fuse lamps in anyway as it was clear that the incans were just cooking the crap out of the plastic. I had to shorten them slightly as they were too long to snap in. How I did this was just heating up the end caps of the fuse lamps and pressing down, as apparently the end caps are only held onto the circuit board by solder. I also replaced both "2" and "4" bulbs with the ones that I got from dgwojo, as well as replacing the backlight for the digital indicator with the LED I got from him.

Everything works great and is nice and cool now, hope this thread helps someone. dgwojo now has the specs for all these bulbs, including the ones I did not replace (the function lights) because they all still worked and let's be honest, I'm a little cheap...