Hello...

I am receiving a Zenith T/O 1000-1 today.. and i have a few questions on it... I havn't worked on much solid state.. and never on a Solid State T/O.. Are the transistors readily available? and if so where.. Is there a thread or website where someone has done a restore on a Transistor T/O .. or even pointers on restoring one... I don't know the actual condition on this radio.. as of yet...I know the battery box is missing and there is no power supply.. also what modern supply should I use and which way is the polarity?... also the top half of the face cover is missing.. would really appreciate and and all help on this soon to be project...

Regards.. Mike

The transistors are readily available - NTE160, NTE 126, and NTE102a. The power supply is 12V, a 3/32"/2.5mm plug with the TIP negative, not the shield. Theres nothing like diode-protection for this so if you get it wrong you will likely break something. There are numerous recent threads on the 3000 which is very similar and most of the same things apply .

I strongly recommend making a battery box/board from "C" cell holders that you can get anywhere. You need 8 cells to run the radio and 1 to run the dial light. I will check the plug polarity later but the CHASSIS is positive.

Likely problem areas - dirty bandswitch, dirty volume control pot, dirty/corroded transistor pins/sockets, bad transistors. Most of the 1000/3000 I have worked on had no issues with electrolytic caps but it can never hurt to replace them. I would suggest trying to fire it up with batteries (ONCE WE HAVE THE CORRECT PLUG POLARITY) and seeing what you have. Like as not, it will work, if not, manipulate the bandswitch back and forth to clean it. If it doesn't work, might have some debugging to do, but cleaning the contacts of everything and removing and reinserting the transistors usually gets it working to some extent. Aside from hooking up the battery backwards, there's not a lot of harm to be done by just trying it.

Brett

p.s. Oh yeah, the power jack is one of the more unreliable parts in the radio. One possible failure mode is that the power plug will work, but it won't work on batteries, because the contacts fail to "make" when the plug is removed. That's another area to carefully clean, but once it stops working because the contacts are sprung, it's very tough to ever get it working again.

This is the battery plug polarity. The 12V polarity is *critical*. The 1.5 volt (dial light) is not critical, it can be either way.

Brett

Thanks Brett...

Got the radio last evening... after opening the back... I could see someone had wires on the battery connector.. but had the polarity reversed.. Guess thats why the guy I bought it from couldn't get it to work... I made up a battery pack using 8 D cells. and hooked it up the right way.. after a little while(it seemed to hesitate) the radio came up..it seems to work on all bands .. the loudness is.. related. to the strenght of the station.. so in otherwords the volume dosn't seem to be what it should be...Question.. could the previous owner do damage by hooking the polarity backwords..? even tho the radio seems to be working fairly well?

Mike

Definitely could damage it, either the electrolytic caps, the transistors, or the resistors around the transistors. I would start with the caps, they could have been bad (classic cause of low volume and other audio quality issues on transistor radios) before, or zapped by reverse voltage.

Brett

I have a very early (1958) leather-covered 1000D, and I did have to replace a couple of the electrolytic capacitors which started to ooze electrolyte! It might be a good idea to visually inspect yours for swelling or leakage.

I wiggled and cleaned the Transistors and sockets... bandswitch.. havn't got to the Caps.. yet.. but after reading about the solar flares.. in another post.. maybe reception is off for that reason... I will still replace the caps.. as soon as I get them


Thanks for the replies...

Mike

A cap that comes off the center lug of the volume control is sorta hidden and hard to get at but do not forget to change it as it will kill the audio in these 1000's. It is a 5 mfd @ 12V electrolytic.

And its quite the little bastard to get to, as well. Not as bad as the same spot on a Royal 7000 but bad enough.

Brett

Hello again...

I have a few LiPO batterys that My son bought to use with An Electric Helicopter.. he no longer has.. These are new.. They are 11.1 volts 2.2amps.. Would it be OK to use as a Battery for the T/O...? its about the size of two D cells end to end...

Mike

Well made up a connector for the Lipo battery.. charged it up.. Works great.. I don't have a battery box.. I guess I will just use some velcro..


mike

Good idea Mike !

For my 1000-D used an 8-AA cell holder from Radio Shack---works well, but no dialight unless another single battery holder is added...

John

The radio should play forever with Mike's 11.1 volt, 2.2 amp battery.

John's solution is a good one since today's AA alkalines will last longer than yesterday's carbon-zinc D-cells. Plus it doesn't add serious weight like D alkalines in the original battery box would.

Dave

yea should last forever.. .. was going to do the AA or C route.. but when i was looking through my battery/battery holder stock i came across the Lipo's.. Didn't have any other use for em...

Mike

Got the radio finished and put back into the cabinet....Works Great!... really impressed with the quality...

Thanks.. All for your help...

Mike