MCS 3245 q-u-e-s-t-i-o-n-s-?

[Navanoise]

I had a similar situation with MCS 3233 but with rubber not metal boot. Here's a link to how I modified the wedge bulb to work. Post #12 with pics.

https://audiokarma.org/forums/index.php?threads/mcs-3233-lamps.284003/#post-11857017

Oh nice. So you can bend the bulb's wires out? Then solder. I might try that as it looks like the most cost effective solution at the point. I'm having a hard time justifying spending $20 on four replenishment sockets and bulbs when I only paid $40 for the whole receiver. Lol. Btw, I stopped at my local vintage stereo repair shop to see if he'd sell any bulbs. Nope. But he did have a nice 3235 for sale for $250. He had it displayed with the Pioneers and Kenwoods of the day. Neat. (Marantz and Sansui had their own sections.)

 

[Navanoise]

So I got the two bulbs replaced that were out. I decided to go to Auto Zone and found 2 Sylvania 12v 5w lamps that look just like the ones I saw on eBay. I bent the leads out and soldered the wires on and wrapped them individually in electrical tape. Turns out the two end ones with the metal boots that were out were different than the two center ones which just had wires in a rubber sleeve coming out of the back. The new bulbs fit perfectly in the holders. $7. Looks good I think! Fingers crossed these will be ok. Thanks for the ideas all.

 

[Navanoise]

Finally got them set up! They wowed the crowed cranking out tons of vinyl last night for a holiday gathering.

 

[Racingh11]

Thank you TomBig58!

So, I've been looking into bulb replacement options. Still considering LED mentioned above, but came across this guy on eBay selling these as incandescent replacements. for original 3245 bulbs.

And I pulled a burnt bulb from the reflector on mine and here's what it looks like (came out easily).

Obviously the eBay ones are different and would somehow need to be soldered and there's no metal sleeve to insert into socket. I'm kinda liking the original as far as brightness/feel, but looks like snipping some wires and replacing with the LED sockets sets mentioned above would not be too difficult. hmmmmm

That bulb is the 194 style I mentioned that matches those sockets. He is marking them up as something special, but you can get them for much less when you look up 194 bulbs.

 

[Racingh11]

So I got the two bulbs replaced that were out. I decided to go to Auto Zone and found 2 Sylvania 12v 5w lamps that look just like the ones I saw on eBay. I bent the leads out and soldered the wires on and wrapped them individually in electrical tape. Turns out the two end ones with the metal boots that were out were different than the two center ones which just had wires in a rubber sleeve coming out of the back. The new bulbs fit perfectly in the holders. $7. Looks good I think! Fingers crossed these will be ok. Thanks for the ideas all.

The originals are 150mA. 5 amp is way too much. They sell 194 bulbs at any auto parts store. Common for side marker lamps and glove boxes.

 

[Navanoise]

The originals are 150mA. 5 amp is way too much. They sell 194 bulbs at any auto parts store. Common for side marker lamps and glove boxes.

Thank you. There were many options with similar bulb style at lower watts. Maybe one could go lower. No 194 bulbs though where I shopped. I took a stab. So far so good though, but I want to get it right if those bulbs aren't correct.

 

[Racingh11]

I completely recapped and set bias specs on a 3245 receiver this week and gave it a thorough test afterward. It is much better than the .2 - .3% THD factory rating.
Tested distortion from input to output and power amp section independently. It was checked with a Tektronix AA501 and SG505 distortion analyzer and oscillator, at rated power of 45 watts into 8 ohm with both channels driven. Then rise / fall time and slew rates were tested with a Tektronix PG506 calibration generator. Results are as follows:

% THD
L R
20hz .013 .01
100 .013 .008
1k .031 .038
5k .059 .052
10k .052 .046
20k .039 .030


% THD power amp section only
L R
20hz .0021 .0029
100 .0025 .0023
1k .015 .011
5k .025 .019
10k .024 .019
20k .027 .029


rise time: 7 uS
fall time: 6 uS
slew rate: 7.2 V/uS =21khz at rated power, or 128khz at 10 watt

 

[Racingh11]

Thank you. There were many options with similar bulb style at lower watts. Maybe one could go lower. No 194 bulbs though where I shopped. I took a stab. So far so good though, but I want to get it right if those bulbs aren't correct.

I see, odd they didn't have them. I just realized you said 5 watt, not amp. The originals were 1.8 watt for comparison.

 

[Racingh11]

Thank you. There were many options with similar bulb style at lower watts. Maybe one could go lower. No 194 bulbs though where I shopped. I took a stab. So far so good though, but I want to get it right if those bulbs aren't correct.

I guess if the transformer doesn't get hot from the bulbs you tried, and you like the level of light they put out, then maybe they are fine to use. I'm not sure what the capability of that transformer winding actually is. It may handle the load. Maybe just leave it on for and hour with no music on and feel the temp of the transformer, Leave the cover off when you do it so the bulbs don't heat everything up and skew the results.

 

[Navanoise]

I see, odd they didn't have them. I just realized you said 5 watt, not amp. The originals were 1.8 watt for comparison.

Thanks for that info and about checking the transformer. There were many options closer to 1.8 watts. At some point, probably when the two older bulbs go I'll look into a different bulb set up.I do like the warmer feel of the incandescent bulbs. Warm white LEDs where a little pricey for my budget when I looked into them. I've given this receiver a real workout over the past week+ and so far it's passing all the tests performance-wise/sound-wise. I'm a happy camper. I'm just a amateur vintage gear enthusiast with not much technical understanding of all the inner workings or skill to do too many repairs myself. One day I might gather up the courage and replace the capacitors. lol Thank again.

 

[Racingh11]

Both of the 3840 and 3842 are 45 wpc. Only difference is cosmetic - color scheme on the face. Same with the 3860 and 3862. Both are 60 wpc, with differences only on the face. Nice sounding amps, but very few have survived over the years. They were Panasonic rebadges, with a few cosmetic changes. The 3760 tuner looks like a Technics ST-Z45 to me. The amps look 'somewhat' similar to a Technics SU-Z45 (maybe more like the Panasonic version?).

You are correct. I finally took a picture of the 3760 & 3762 tuners. It is the color of the plastic bezel that is different. Not the best picture, but it can be seen.

 

[booted]

i just picked one these up yesterday(Sunday) MCS 3245. running this one till my realistic sta 2080 is back from repair. The right channel on the 2080 is weaker than the left. I am surprised how loud the mcs can get for only 45wpc.

 

[Navanoise]

Super happy with mine still. Have really put it through the vinyl listening ringer over the last several months and it's sounding like a champ.

 

[Psychophonic]

I picked up a 3245 just today, along with an MCS turntable and cassette deck. The 3245 powers on and is working. However, the right channel fuse button was popped out. Upon resetting, I blew a woofer. Sadly, I was also testing a pair of old Pioneer CS-66e’s. So I now have to find a replacement woofer for that. Anyway..

I see a charred resistor on the vertical board toward to back of the chassis. I didn’t see/smell smoke when I blew the woofer, so I think it was already there. The resistor is shot, so I cannot determine the value. On the board, the resistor label is charred so I can’t read the third number (R93_).

I’m not a tech. I can mod, troubleshoot, and repair basic guitar pedals and such. I can somewhat use a voltage meter and my soldering skills are adequate.

Additional concerns:
1. As far as high voltage, I am unsure what not to touch. I see the huge caps over on the left, I’m staying away from those. What about the board in question?

2. Seems about impossible to remove that board to replace the burnt resistor.

 

[Psychophonic]

i just picked one these up yesterday(Sunday) MCS 3245. running this one till my realistic sta 2080 is back from repair. The right channel on the 2080 is weaker than the left. I am surprised how loud the mcs can get for only 45wpc.

How do you like your 3245? Have you opened it up? I could use a shot of the vertical board so I can identify my burnt resistor.

 

[booted]

so far my mcs has been good. Had to replace the bulbs though.. next time i open it up i will take a picture.

[/QUOTE]

 

[Racingh11]

How do you like your 3245? Have you opened it up? I could use a shot of the vertical board so I can identify my burnt resistor."

You should be able to see what it is on the other channel, they are close to a mirror image. I have a manual at a different location. I will let you know what it is for sure when I get it. Maybe tonight.

 

[nolasally]

@Psychophonic LOL. I saw that CL listing and passed it on to fellow ak horder. In my heyday Id have been all over it! Knowing most of that stack of MCS & Adcom would need work I passed... Already have piles of gear to fix. GLWS on MCS stuff and GFA-555...

 

[Psychophonic]

Thanks for the replies guys. I don’t think I want to mess with this one, I just don’t think I have the skills to repair it. Removing the board is not a job for me. It looks like I’d have to disassemble many things to get to it. It’s a bummer, but I’m going to let someone with more experience have at it.

 

[nolasally]

@Psychophonic agreed...I would have fixed that adcom though... Good amp and easy to work on....