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Scott 388 rebuild

podbaydoors

podbaydoors

AK Subscriber
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Hi all,

There is something cool about being fairly sure that you are the only person in the entire world doing something at any particular point in time. I am currently engaged in a complete rebuild of a mid 1966 Scott 388.
Everything on this puppy is separated into functional modules and located quite accessibly on the aluminum chassis. No wonder that when this was new, it cost 499.99, that's $3,700.00 in today's money.

First step has been to replace EVERY one of the 50 year old electrolytic caps.
Started with the power supply, done.
Working on the driver boards now (each channel separate). Lots of Tennessee Electronics caps, never heard of them before.
Some of the transistors are socketed, some not.
Never been crazy about phenolic circuit boards, my experience has been that they tended to warp and separate the traces as they age.
Next will be the preamp boards.
Final will be the RF sections.
I know, the unit itself isn't very collectible or valuable, but I have always had an affinity for vacuum tube Scott, now I'm doing the solid state stuff.
If anyone needs it, I have the schematics and the Scott service manual which I can scan if needed.

Regards,

Lou
 
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The unit is finished. Sounds great.
Replaced every single electrolytic cap in it.
The preamp boards were a surprise with the inductor in the RIAA eq.
I really do like the modular single channel approach.
Can't imagine what it would cost to build a discrete component, individual channel per board configuration today.
It is proudly adorning the home thee - ate - her setup in the living room currently running with a pair of KLH model six.
Next up in the queue is a Dynaco PAT4 and ST-150 pair.
upload_2016-9-22_14-36-22.png

View of the preamp board before rework.

Cheers!

Lou
 
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I just finished repairing a Scott 350C tuner, the black Callins electrolytic was the only dead one. It seems those are always dead no matter what they're in.

Craig
 
Just an update...
Two years later, still working great as a daily driver. Only change was from KLH 6 to AR 2AX. I rotated a pair of AR 3A but the output transistors didn’t appreciate the 4 ohm load.
They warmed up a bit more than I liked with any significant power output.
 
Listening to a 388b this morning. Really enjoying the FM reception and sound. For a 50 year old receiver that has had zero work done to it, am amazed because it is beating down some very well established receivers that I have had in the past. I am mostly a tube aficionado, but this old receiver really boogies, is not even getting warm after 5 hours running, and seems to have some real power behind the volume control. Using a refurbished pair of Beovox S45-2 speakers, a small 3-way design.
 
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The 388B was a lot further down the solid state development line.
It did continue the modular concept of putting the various functional sections on individual boards though.
It also had considerably greater power output also.
The 388 was pretty much at the limit pushing 30 watts continuous through both channels. The 388B surpassed that by far.
I had a 388B in High School connected to a pair of 15” Jensen Triaxials in homemade corner horns.
That was a whole lotta sound!
 
Still working fine, running the KLH-6 again.
Some pix of the modular chassis design.
upload_2020-3-3_8-23-57.png

upload_2020-3-3_8-24-57.png

upload_2020-3-3_8-25-46.png

upload_2020-3-3_8-27-27.png

upload_2020-3-3_8-28-5.png

upload_2020-3-3_8-29-46.png

Just imagine the cost to assemble an all discrete component receiver today!
 
Curses!
I hadn’t used the 388 since last year.
A user asking about the service info reminded me of it.
I replied that the manual was posted to HiFi engine so everyone can reference it.
Pulled it out set it up and was enjoying when much to my dismay the beast took a dump and now the left channel has a non functional driver board. The Scott house semiconductor naming scheme is infuriating. Rather than using industry standard nomenclature they had to use in house naming conventions. And it’s the odd pnp. Guess I’ll have to try a few to see what sounds acceptable.
 
It has previously been noted that the outstanding early 312D tuner, with its 3-FET/1-NPN front end and its 4-IC IF, was preceded by late 312Cs with the same configuration. The earliest such 312C I've been aware of is SN 397251.

The same config is found in the Scott 348B FM receiver and 388B AM/FM receiver, as well as late 348 and 388 receivers. A 388 with SN 385294, currently online, is an example.
 
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podbaydoors said:
Hi all,

There is something cool about being fairly sure that you are the only person in the entire world doing something at any particular point in time. I am currently engaged in a complete rebuild of a mid 1966 Scott 388.
Everything on this puppy is separated into functional modules and located quite accessibly on the aluminum chassis. No wonder that when this was new, it cost 499.99, that's $3,700.00 in today's money.

First step has been to replace EVERY one of the 50 year old electrolytic caps.
Started with the power supply, done.
Working on the driver boards now (each channel separate). Lots of Tennessee Electronics caps, never heard of them before.
Some of the transistors are socketed, some not.
Never been crazy about phenolic circuit boards, my experience has been that they tended to warp and separate the traces as they age.
Next will be the preamp boards.
Final will be the RF sections.
I know, the unit itself isn't very collectible or valuable, but I have always had an affinity for vacuum tube Scott, now I'm doing the solid state stuff.
If anyone needs it, I have the schematics and the Scott service manual which I can scan if needed.

Regards,

Lou
Click to expand...
Hi Lou : I am in need of a schematic for a Scott 388B Can't find a complete one. Regards , Ted (tedpask@yahoo.com)
 
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