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Old 12th Feb 2019, 5:46 pm   #41
Humptydumpty
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Default Re: Capacitors for Trio 9R 59D

This is the offending resistor if thats what its called ,. Easy to replace once i know what it is . Most of these parts are not available on the net .This is an old picture bofore i re wired the 240v mains lead .You can see the reason why , the not . Its the cylindrical item thats getting hot on the left hand side its about 1/4 by about 2 " long .
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Old 12th Feb 2019, 6:27 pm   #42
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Default Re: Capacitors for Trio 9R 59D

Why do you want to replace the resistor? It is supposed to get hot. That is why it is so big.
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Old 12th Feb 2019, 6:50 pm   #43
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Default Re: Capacitors for Trio 9R 59D

So you say then Dave nothing wrong ?. I thought for a moment i had found the problem .So what is it there for .
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Old 12th Feb 2019, 7:29 pm   #44
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Default Re: Capacitors for Trio 9R 59D

I know now its reason its there thanks to google . . But there again it wont hurt to replace it with a new one . Who knows where i can get one but more important is what do i ask for .
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Old 12th Feb 2019, 10:00 pm   #45
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Default Re: Capacitors for Trio 9R 59D

I don't want to dampen your enthusiasm Trev, and I really don't know how to say this without sounding scornful , but it seems to me that the reason there have now been more than 280 posts in six threads concerning your 9R59D sets, with many forum members trying to offer you helpful advice, is that you seem not to have made any real attempt to study the circuit and to understand how the components in the set relate to the circuit, nor to have carried out any Voltage or current tests to compare with the circuit, except when advised to do so around the audio valve.

I'm at a loss as to why you're looking on google for answers and not at the circuit.

If you look at the component in question, (which by the way shows no signs of overheating), it's clearly a high Wattage resistor and you will see a resistance value marked on it, and most likely, the Wattage. Most sets of any make or model have several high Wattage resistors in the power supply section and yours is no different. You'll also see that there are other components to which the resistor in question is connected, and if you study the circuit, you'll be able identify the resistor.

On a quick glance at the circuit, there are three high Wattage resistors, namely, R37: 2K2 8 Watts; R38 and R39, both 1K 4 Watts. They'll all get quite hot in normal use - most likely, too hot to touch. Are you planning to replace them all on a whim to no good effect? If so, modern ones won’t look like that - they’ll be shorter, will be square in section and will be white ceramic.

You're correct in saying that replacing the resistor in question 'won't hurt' but neither will it do any good and it certainly won't have any bearing of your desire to reduce the hum level. But as I've said before, it's your set to do with what you wish, so if you wish to change any or all of the high wattage resistors, you'll find suitable modern ceramic ones here:

These are ten Watts:

https://www.esr.co.uk/components/pro...-resistors.htm

These are five Watts:

https://www.esr.co.uk/components/pro...-resistors.htm

I hope that might answer your query, ("What is it and where do I get one?") but it won't, I think, help you make any progress towards reducing the undesired hum level.

You could, if you wished, (by using Ohm's Law), check how much current is being drawn through each resistor by checking with a meter on the Volts range across the resistor to see what Voltage it drops. If you then divide the resistance into the Voltage, it will tell you how much current in Amps is being drawn. (It will be much less than an Amp). If you then multiply that current by the Voltage, you'll know how many Watts is being dissipated. That will give you an indication as to whether excess current is being drawn.

As one set is working to your liking, it might be useful to check the Voltages of both sets compared to the circuit, and to note any discrepancies. It would also be useful to list the resistor values on the circuit, and to compare those in the sets, noting any that are 20% or more in excess of their stated values. That can be useful in highlighting any that are causing lower than specified Voltages at various points.

Good luck in your endeavours.
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Old 13th Feb 2019, 11:00 am   #46
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Default Re: Capacitors for Trio 9R 59D

David i only took this on myself because at the time i could find no one to do it .And you said yourself that to repair it would cost more than the set was worth.
Thank you for all your help in the past .
This is about the third time i have been told about how many post thiese Trios have made . A lot of this information is way above my head .Dont understand half of it . We all need to start someplace .And at 74 it hard to pick this info up . I think i have done well to get as far as i have . Would not have got this far without all you good members . So i think its time to bow out on this one for now , and let you ponder on easy tasks. Thank you all .
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Old 13th Feb 2019, 11:54 am   #47
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Default Re: Capacitors for Trio 9R 59D

Changing components for no reason is a good way to introduce new faults into a set, as many 're-cappers' have found. If a resistor which is supposed to be hot is hot then that is a good reason to leave it in place; if it were cold then you would need to investigate why.
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Old 13th Feb 2019, 3:29 pm   #48
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Default Re: Capacitors for Trio 9R 59D

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Originally Posted by Humptydumpty View Post
David A lot of this information is way above my head.
That's fine. Nobody was born already knowing anything. We've all been there.

The way to handle this is to elevate the level of your head

There are plenty of people on here with plenty of knowledge, AND the inclination to share it. It is possible to learn a lot. It won't be fast but it will be certain. Also what you learn is applicable to plenty of other things.

You know the old joke about the man who takes his whatever to a repairer, and all the repairer does is hit it with a hammer and it's fixed, the punch line was that it was 50p for hitting it and a tenner for knowing where to hit it? radio and electronics is like that. Parts are often cheap, but knowledge is priceless.

That resistor is in there to do a job. It is big because that job involves the dissipation of power and a smaller resistor would get much hotter and too small a resistor would burn out. I don't know the circuit, but it is probably what's called a 'dropper' dropping the HT voltage down to a lower voltage for circuitry which benefits from or requires a lower voltage. It's doing a necessary job, It seems to be working and it looks to be in good condition.

The art lies in finding out WHICH parts to change in your radio and which to leave alone.

In changing any part, there is a risk of making a mistake. Fitting the wrong part, missing a wire off, doing a bad solder joint, melting a bit of insulation. Change everything and you have to be a VERY diligent worker to have any chance of it working afterwards. Even careful people have occasional problems. If you want to change all the parts, where do you stop? you could just buy a new radio.

What you're wanting to do requires a fair amount of knowledge and a fair amount of effort. No-one could make a business out of it and expect to win much trade at the price of a reasonable hourly rate. This is why you haven't found anyone interested in doing it as a business proposition. Almost all the repair shops closed a decade or two ago. They simply couldn't stay afloat.

This leaves you with only one way forward. You have to do it yourself.

To do that, you have to acquire the necessary knowledge. A fair amount of effort is involved. Is it impossible? No.... it's not even difficult.

You've been asking: I want to change this cmponent... what sort do I need to buy?

What you should be asking before that is : How do I find out which components I ought to change.

David (Another David!)
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Old 13th Feb 2019, 5:53 pm   #49
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Default Re: Capacitors for Trio 9R 59D

Quote:
Originally Posted by G8HQP Dave View Post
Why do you want to replace the resistor? It is supposed to get hot. That is why it is so big.
G8HQP thank you .I looked in side the other receiver and sure enough the resistor was just the same after it had been on for a few min.
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Old 13th Feb 2019, 6:02 pm   #50
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Default Re: Capacitors for Trio 9R 59D

RadioWrangler you are so right . And i do check things on the schematic but the resistor gives no value i can see L29 SP 2.2 kh on the side of it . David posted a link but i am still stuck with what 10 w resistors i need and also the 5w type. I see 2k2 is that 2.2 ?
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Old 13th Feb 2019, 6:33 pm   #51
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Default Re: Capacitors for Trio 9R 59D

Quote:
Originally Posted by Humptydumpty View Post
David posted a link but i am still stuck with what 10 w resistors i need and also the 5w type. I see 2k2 is that 2.2 ?
Why do you want to replace the resistor? Have you tested it to prove it's faulty? David described how to do that in post #45.

The service manual shows that the resistors are wire wound and rated at 4W and 8W so IF you needed to replace them you could use 5W and 10W versions with a similar resistance and tolerance.

What exactly is wrong with your radio? There've been so many threads and so many posts that I'm no longer sure.
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Old 13th Feb 2019, 7:07 pm   #52
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Default Re: Capacitors for Trio 9R 59D

RadioWrangler it will be a waste ofyour time looking .
Now i know the reason why it is hot . And there for the wont be a reason to change it.
Looks as if i will just have to grin and bear it for now .HUM HUM
That is for both receivers .
Dont think they are such a good receiver after all .
I liked the band spread on these .And the new receivers dont have this .And it takes all the enjoyment out of the search . I will put all three up for sale the 2 Trios and the Frog 7 and get a simple up to date radio .
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Old 13th Feb 2019, 7:11 pm   #53
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Default Re: Capacitors for Trio 9R 59D

Post closed .
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Old 13th Feb 2019, 8:14 pm   #54
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Default Re: Capacitors for Trio 9R 59D

Quote:
Originally Posted by Humptydumpty View Post
RadioWrangler you are so right . And i do check things on the schematic but the resistor gives no value i can see L29 SP 2.2 kh on the side of it . David posted a link but i am still stuck with what 10 w resistors i need and also the 5w type. I see 2k2 is that 2.2 ?
As to being 'stuck with what 10W & 5W resistors you need' - I doubt that you need any.

2K2 is what used to be called in days of yore 2,200 or 2.2K Ohms, K meaning 1,000 (as in 1,000 grams = 1 kilogram, 1,000 Metres = 1 kilometre).

'L29 SP' was probably a 'house code' used by Trio. ('L' normally denotes a coil or a choke). 2.2k means 2,200 Ohms. As I explained earlier, by checking what other components it's connected to, by measuring it's resistance and referring to the circuit, you would identify that it's R39 in the power supply circuit. I'd reiterate that by checking the voltage drop across that resistor, you can determine how much current is being drawn and how many Watts is being dissipated. You'd most likely discover that it's well within its 8 Watt rating.

If you look for a 2.2K resistor, you probably won't find one, because decades ago, to help avoid errors, the resistor numbering system was changed and doesn't contain any decimal points. Hence, a 0.22 Ohm resistor is 0R22, a 2.2 Ohm resistor is written 2R2, a 22 Ohm resistor is 22R, a 220 Ohm resistor is 220R, a 2,200 Ohm (or 2.2K) is 2K2, then 220K, then not 2.2Meg but 2M2, then 22M. (And the same of course for all the decades of values - 3k3, 4K7 5k6 etc).

As to the high number of posts, there's no limit of course, while ever the thread stays on track.

The reason I mentioned it is that I and others have suggested on several occasions how to carry out logical tests. For example, that you should check the voltages as indicated on the circuit as I did in my previous post, and if the voltages vary significantly, that would need to be investigated. Long ago I said for example that if you start with the power supply, is there 160V AC into the rectifiers? If yes, is there 210V DC on the rectifier output? If it was much lower than that, the rectifiers would be suspect and all of the HT voltages around the set would be low. If its 210V or thereabouts, start checking the DC voltages elsewhere by referring to the circuit.

But I can't see any evidence of you having carried out any such tests. Many of the posts have been down to you wanting to change components on a whim rather than by methodical diagnosis, with other forum members urging you not to. This latest desire to change a high Wattage resistor because it's getting hot rather than checking what current it's passing, is a case in point.

I think you were to get an auto-ranging digital multi-meter to carry out such tests. Has it arrived, and have you used it yet?

I'm not having a pop at you Trev - I just think it's rather a pity that so much of your considerable effort has been misdirected to no good effect. You're right that we all have to start somewhere, but if advice is proffered and not put to use, you're unlikely to make much headway. The whole essence of the forum is for members to seek and to offer advice, encouragement and support.

There's nothing wrong with being 74 by the way. I'm 80 and have yet to decide what I want to be when I grow up.

'The woods would be very silent if the only birds that sang were those that sang the best'.
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Old 13th Feb 2019, 9:10 pm   #55
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Default Re: Capacitors for Trio 9R 59D

I'm afraid David is right Trev. Advice is freely given and the Forum is outstandingly helpful, welcoming and supportive. That's why people joining invariably say "treat me gently" [as if we'd do anything else] they've often had a different experience elsewhere! Overall, the clue is in the word Forum ie a peer discussion and sharing not just [effectively] answering more questions or providing a one to one tutorial. That's not very rewarding or enjoyable for anyone in the end. Yes we all had to start somewhere but without an amazing Internet resource [like the existing info on here] or easy access to other people.

If you don't understand very much, as you say [p46] it may not be anyone's fault or solvable just through more questions. I think that attitude is crucial. You may well have just misunderstood the ethos from the beginning [somehow] but it's never too late-less is more as they say!! Most people who are enthusiastic about your set will indeed say that it wasn't particularly an advanced design but affordable. The fact that so many users recall them with pleasure and devised modifications to improve things is significant. They though it was worth making the effort.

Cheers,
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Old 14th Feb 2019, 10:24 am   #56
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Default Re: Capacitors for Trio 9R 59D

G4EBT Dave now you tell me about the rectifier ,what is a rectifier and i will check it .And yes i did have a new meter . But i have not used it as yet .
But we are off again on another tangent . Do you think we should carry on ?
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Old 14th Feb 2019, 10:42 am   #57
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Default Re: Capacitors for Trio 9R 59D

The rectifiers (aks diodes) are the two white components shown in the picture in post #41. Each one has a black capacitor in parallel with it. Their circuit designations are D6 (Diode 6) and D7.

Diodes and rectifiers only allow current to pass in one direction, so they can be used to convert Alternating Current (AC) from the mains supply to Direct Current (DC) for the radio's High Tension (HT) supply.

Measure the AC voltage at the transformer end of each diode with respect to (wrt) chassis and the DC voltage at the smoothing capacitor end of each diode wrt chassis. Compare your readings with those clearly shown on the circuit diagram.

Also note from the circuit diagram the positions of the wire wound resistors R37, R38 and R39 which, along with the smoothing capacitors, form the smoothing circuits which eliminate most of the mains hum which would otherwise be present on the DC supply.

The diagram attached is for the US version of the radio, but the measured voltages will be the same for the 230VAC UK version
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Old 14th Feb 2019, 11:00 am   #58
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Default Re: Capacitors for Trio 9R 59D

Dave are these the two grey components in the top of the picture, are they the rectifiers ? no D6 and D7 on the schematic .It did say they were close to the main transformer . Picture taken before i moved the ht cable and the knot .
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Old 14th Feb 2019, 11:09 am   #59
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Default Re: Capacitors for Trio 9R 59D

They look odd but I think so.
Easy enough to check with a meter on "Diode" range. Read one way but not the other.
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Old 14th Feb 2019, 11:10 am   #60
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Default Re: Capacitors for Trio 9R 59D

I can check voltage to rectifiers .But how to check the rectifier output?

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