Newbie with an 800B

[Day Radebaugh]

Hello:

I'm Day Radebaugh from El Dorado, Kansas, and was happy to find this site.  30 years ago, when I was a starving student, I lived in a house in Baltimore that was in the process of being sold.  They had an old Scott console (with a phonograph, as i recall) which i bought for $5.  I couldn't keep the cabinet, but kept all but the phonograph.  It's been stored inside ever since.

So now I'd like to have it restored, and I would build a new console to contain it.  Do you have any suggestions about how to proceed?  Anyone you know of who could tackle a functional restoration of this unit?

Thanks for your help.

Day Radebaugh

[Day Radebaugh]

TungSol KT-66's arrived.  Can I plug them in and turn it on?  Any biasing necessary?

[Day Radebaugh]

Replaced the tubes, and the sound is clearly bigger and more full.  The 6L6's they replaced looked rather new, and were labelled Tung-Sol 6L6WGB, although I could not find a date.

[Day Radebaugh]

Have had the radio on for about 4 hrs on local FM.  Tuning has not drifted appreciably, and sound is wonderful.  A truly impressive performance for 70+ years old.

[Day Radebaugh]

Turned on the 800B the other day, the relays came on, magic eyes started to light up, then everything went dark.  Relays still work, but magic eyes won't light up.

Here is my question: I have to take the unit for servicing, but it will be difficult to transport the speaker.  Is there a substitute speaker that can be attached for troubleshooting?  Is there a dummy load I can supply instead so that we can figure out the problem?

Thanks

[Bob Bell]

The speaker - on my unit anyway - is wired in such a way that the unit cannot be turned on without it being connected. In other words, having the speaker connected completes the power circuit. 

Bob

[Kent King]

Bob - That's just a jumper on the speaker plug, easily bypassed, as long as you have a substitute load and field. - Kent

[Kent King]

Did you check the fuse? It's probably ok since the relays are working. Sounds like the B+ is gone, shouldn't be a difficult fix...

Day Radebaugh said:

Turned on the 800B the other day, the relays came on, magic eyes started to light up, then everything went dark.  Relays still work, but magic eyes won't light up.

Here is my question: I have to take the unit for servicing, but it will be difficult to transport the speaker.  Is there a substitute speaker that can be attached for troubleshooting?  Is there a dummy load I can supply instead so that we can figure out the problem?

Thanks

[Day Radebaugh]

I read the circuit description and studied the schematic.  Although B+ is not mentioned specifically, my guess is that the symptoms I reported implicate the rectifier tubes v23 and V24 and filter V22 in the power supply.  Does this seem reasonable?

[Kent King]

Yes, those create the B+ voltage. But the tubes are seldom the issue...there are capacitors and resistors much more likely to be at fault.

[Day Radebaugh]

Thanks.  That tells me how to get going on this issue.

[Day Radebaugh]

Would a newbie like me be able to get the units down on the bench, turn it on, and check voltages for various components without blowing himself up?  Is that the way one would go about troubleshooting?  I'd like to use this event to learn a little more about the radio, and I have just about all the documentation available...Sam's plus the Scott stuff.

Thanks

[Day Radebaugh]

Just discovered the main transformer on the power supply chassis (T9 on attached) is shorted out.  Does anyone know where I might find a replacement?

Thanks800B-Schematic-PS.jpg