Knight Star Roamer - Looking for manual or schematic

[Rnktapp]

Hello,
I recently picked up a Star Roamer at a garage sale for a few bucks, and the tubes light up (after replacing 2) but no sound from speaker, and I would like to do some voltage measurements and check the wiring. Does Anyone have the manual for this or just plain schematic?
Thanks,
Richard

 

[stevez]

If you can post a picture I might be able to help. I have a nice Knight but this version didn't have a 'name' so I don't know if it's the Star Roamer or something close. I have manuals/schematics for it. If you have what I have it's worth fixing - decent quality receiver given the technology.

 

[Rnktapp]

Here's a pic of the Knight Star Roamer

Here's a picture of the Star Roamer, hope this helps.

 

[stevez]

No, not the one. They were popular and it's likely you'll find one eventually. Check in shortwave listening (SWL) forums and you'll find one. Radiodaze, a company near me, may be able to help. Don't give up - that was a nice radio too -all things considered.

 

[Nigel Goodwin]

Valve/tube radios are usually pretty simple to repair, you often don't need a circuit, as long as you have the pinouts of the valves - so you know what voltages should be where.

 

[stevez]

I just sent you a link to a site where there is a pdf manual. I'd start by checking the power supply, particularly the filter capacitors. Some people would suggest you not even turn it on until verifying that the filter caps are ok.

The pros like Nigel might have different advice but lacking a schematic diagram you can usually do things like make sure each tube/valve does glow. You should be able to see the power supply, particularly the high voltage side and filter caps (the largest ones in there, quite often "cans" on top of the chassis) and see if there is high voltage (often called B+). If the wiring is hard to follow you can often see the plate on a tube thru the glass and find the pin - check that pin for relatively high voltage - usually will be over 100 volts - could be 250 volts or more.

 

[Nigel Goodwin]

I just sent you a link to a site where there is a pdf manual. I'd start by checking the power supply, particularly the filter capacitors. Some people would suggest you not even turn it on until verifying that the filter caps are ok.

Yes, old electrolytics can explode if they haven't been used for years, there have been a number of designs over the years for "reforming" the capacitors - basically gently powering them up, giving the capacitor time for the electrolyte insulation to build up.

One good idea you may not be aware of?, it's good practice to work with only one hand on valve equipment (or any high voltage equipment!). So if you're right handed?, keep your left hand firmly in your pocket at all times while working on the radio! - it prevents the possibility of a shock from hand to hand, directly through the heart!.

 

[Rnktapp]

Progress with the Star Roamer and question about S meter

Thanks all for the helpful tips. I do know to keep one hand in my pocket or at least off the chassis
I've tried the link at bama.edu, and the manual must have been taken off the site because I can't view it.
There's plenty of sites SELLING the manual but with the couple bucks I paid for the radio I'd kinda hate to pay 20 bucks for the manual, I might not have a choice, I don't know. I'll try a Shortwave Listeners' forum first. I can probably get by without one, but it would be nice to have one.

Last night I got into the radio to see what I could find. All 4 tubes light up, and after jiggling with the litz wires? at the speaker, I got a faint hum with the volume all the way up. Same very faint hum with very little volume across all the bands. It has a total of 5 electrolytic caps, and they are all the large cylinder type, probably dried out from age. So I think my next step is to replace them.

Question about the S meter. The needle on the S meter is resting all the way to the right, the high side, with radio on or off. If I tap it it swings to the left a little and then comes back to rest at the high side. Could this be normal, and if not, is the meter wired backwards? Or is the meter upside-down and the paper meter scale right side up? (This radio may have been built from a kit.)

 

[stevez]

Not sure if you considered this but unless you know otherwise, the radio might never have worked properly. After doing a few checks it might be wise to check to see if the wiring matches the schematics. If you get the manual this should not be too tough. The did an incredible job with documentation back then.

I thought something was there last night on BAMA - I'll check later. There was a manual for my Knightkit.

Nigel and other pros would know this better than I - use extra caution when working on an old radio. Some were line powered, no transformer, chassis was the neutral (which could be well above earth or ground in some situations). I recall connecting a 110 volt light bulb between a chassis and ground - it was very bright suggesting 110 volts between the chassis and ground. Filament circuits on these were in series and added up to 110 volts - a 50C5 and 35W4 were added to some 12 volt tubes to get to 110 or so volts. Not good practice it seemed but quite common in less expensive radios.

 

[Rnktapp]

got the manual, and Thanks

I went back to the Bama site, and got it to download, but my Adobe Acrobat wasn't working. It was version 5. So I downloaded version 6 and it worked fine. A note to anyone using the Bama site. It looks to me to be a busy server, and you might not get in the first time. If a message comes back "page not available" just keep trying.

Got the Star Roamer working, and it works really well. It had a lot of intermittent shorts, loose tube pin connections, and switch contacts that needed cleaning. I listened to Radio Taiwan International on it the other night, plus a lot of other shortwave stations. The only thing I have to track down now is why the S meter doesn't work. I took another picture of the radio after it was cleaned up and fixed. Here it is. Thanks again for the help.

 

[stevez]

Thanks for sharing. Looks like you've got yourself a nice radio. I have some old meters like that - contact me if the meter is found to be faulty.

With my Knight Kit I was plagued by all sorts of odd noises from about 6 mHz down. I live about 2 miles from a 50 kw AM BCB station and wondered if that couldn't be the source. I put together a relatively simple BCB filter that pushes down the relative strength of anything below 2 mHz or so. With some experimentation it was clear that this made much of the noise go away without affecting signals above 2 mHz. I've since constructed better filters. In all cases the filters are made up of mica capacitors and inductors that are hand-wound (toroidal).

I mention this in case you experience similar things. The better BCB filter design comes from one of the ARRL Handbooks - probably 1999 edition but it may be in others.

 

[WA0URJ]

Could someone send me a link to download a copy of the Knightkit Star Roamer shortwave Radio ? Thank You.

 

[Norator]

Now that it works I guess you should take voltage readings at all tube pins, "for the next time."

 

[Mike - K8LH]

Congrats' on getting the Star Roamer running. This was my first electronic kit back in the 60's. I seem to recall it cost around $39.95 or so... I collected lots of QSL cards from international broadcast stations over the next couple years.

Cheerful regards, Mike