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 Info required on Monarch UA8 radiogram
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 Return to top of page · Post #: 1 · Written at 9:42:15 PM on 19 October 2021.
SteveC's Gravatar
 Location: Sydney, NSW
 Member since 19 October 2021
 Member #: 2468
 Postcount: 4

Hi all,

Our son has inherited this unit and wants my help in restoring it. I have not seen it yet, but I talked him through some things and at least the amp section makes noise when the needle is stroked. He has cleaned and lubricated the jammed idler wheel mechanism and the turntable now spins. At this stage we do not know if it is running at the correct speed, that will be the next test with a strobe disc. The idler wheel is in good condition. He does not have any records to use at this stage.

What has led me to here is that he asked me if he could borrow some of my old records. Bear in mind I have an extensive collection of old vinyl and am obviously reluctant to lend out any good discs, although I have some not so good ones we can use for testing.

My main question, again bear in mind it is appr 40 years since I have serviced this type of gear, is as the UA8 is a mono player and probably has a mono needle and cartridge, will I damage stereo records by playing them with a mono needle / cartridge? I seem to recall that doing this is a no-no. I may need to replace the cartridge with a stereo one and wire it as mono.

Also, ATM the radio section does not appear to be working, more investigation needed, probably needs every paper and electrolytic capacitor replaced.

Regards,

Steve


 
 Return to top of page · Post #: 2 · Written at 8:56:46 AM on 20 October 2021.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 1038

One of these was on my parent's radiogram in the '50s. It played both 78s, 45s & LPs, turn over the stylus accordingly. It was quite reliable and still working in the late 70s when I last saw it. The action was a bit frantic with a load of 78s.

The first LP played on it was a Horrie Dargy Quintet, and I still have a Purple People Eater/Chantilly Lace 45 somewhere. A favourite 78 was Louie Armstrong and Bing Crosby with Gone Fishin' as we did a fair bit of trout fishing in the 50s and '60s. Have fun!.


 
 Return to top of page · Post #: 3 · Written at 5:07:31 PM on 20 October 2021.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1685

The problem with the radio section is possibly a blown valve filament or dirty valve socket. Tell him after he has had it running for a while to switch the unit off and disconnect the power plug from the wall and then see if one of the valves is cold to the touch. If so pull it out and spray contact cleaner into the socket. Then identify the valve and test for continuity between the filement pins. He can identify the filement pins by typing the valve number plus radiomuseum into the web browser and radiomuseum will come up with a pin diagram and the filement pins will be marked either F or H.
But please advise him to never leave the unit on or dont even use it untill its properly serviced. I know you would but I'm just saying.


 
 Return to top of page · Post #: 4 · Written at 2:17:06 PM on 22 October 2021.
SteveC's Gravatar
 Location: Sydney, NSW
 Member since 19 October 2021
 Member #: 2468
 Postcount: 4

I plan on heading over to our son's place tomorrow, so I will be able to check it out more.

I actually still have my Phillips Miniwatt Vacuum Tube Data Manual, 1966 edition.

Any comments re the stylus on stereo LP's? I also suspect the arm down force may be too great.

Regards,

Steve


 
 Return to top of page · Post #: 5 · Written at 5:26:29 PM on 22 October 2021.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 1038

I didn't mention that the stylus on the LP side of the one I remember was mono. I don't know if the stylus load could be reduced enough to ideally suit microgroove records, but it did play them. The onset of stereo led to the radiogram's retirement, and replacement by a hifi system, probably early or mid seventies.


 
 Return to top of page · Post #: 6 · Written at 9:25:01 AM on 26 October 2021.
SteveC's Gravatar
 Location: Sydney, NSW
 Member since 19 October 2021
 Member #: 2468
 Postcount: 4

I visited our son on Saturday and had a quick look. It is safe to power on for short periods. Hopefully it is not a live chassis unit.

They purchased some old lp's economically on line but they don't play well. I have yet to check the turntable speed, I suspect it is slow.

There is a loud hum from the speaker, not controlled by the volume control, obviously the power supply caps will need replacing. If they need replacing so will the other electrolytics as well as any paper caps and resistors gone high or even open circuit. Not to mention old wiring.

The audio section seems OK, rubbing the stylus with my finger produces noise which is controlled by the volume control. However, when playing a record the volume is up and down and not very loud, not as loud as when I tickle the stylus. The pots are scratchy as well, although often a bit of pot lube fixes that. So, sounds to me as though the cartridge is shot, won't be able to be sure until I get a signal generator on the leads.

All in all, I doubt it is economical to repair unless he really wants it done for sentimental reasons. Although I could teach / supervise him, he does not have the skills to do it so I guess it will be up to me.


 
 Return to top of page · Post #: 7 · Written at 7:51:06 PM on 28 October 2021.
BurntOutElectronics's Gravatar
 Location: Alexandra, VIC
 Member since 2 October 2019
 Member #: 2392
 Postcount: 237

Yep, sure sounds like your a-typical valve set in terms of repairs required. Cant really get around it a cheaper way unfortunately.
The only way to do it is to do it right.

In terms of it being a live chassis set, does it have a big power transformer?


 
 Return to top of page · Post #: 8 · Written at 9:19:54 PM on 28 October 2021.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6625

It is safe to power on for short periods.

I used to think that about 33 years ago when I started collecting radios. At the time, the nation's radio fleet was much younger and it was considered safe to bring it home and power it up after dusting off the cobwebs.

Not anymore. These things are just too old to mess about with now and chronic electrical issues are a standard fitment to just about any unrestored radio. Valves are generally considered a consumable - they are just like a light globe only a little more technical. But the valves are usually the electrically strongest part of any radio and will very often outlast capacitors, resistors and coils that are connected to them. In fact, valves often fail only after a passive component has failed just before it and caused an overload.

Assuming that there are no faults with the circuit, the electrical cord and larger capacitors will all require automatic replacement. This should generally only cost about $40.00 and is well worth doing should the radio become a demonstrator or a daily listen. Many radios will sadly also have open-circuit resistors or coils and these will require repair or replacement as well.

There is a loud hum from the speaker

Here's Exhibit A - dried out filter capacitors, which are letting mains hum straight into the system. Best to keep the radio off until it is serviced. If you sincerely believe that repair will be beyond you, the best advice is to join one of the radio clubs and get in contact with a repairer that will have that radio singing like a new one in short time. There are a few members here that also may be able to help. It is money well spent, even if only for the safety aspect.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
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