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Old 2nd Sep 2020, 7:45 pm   #1
Mogga96
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Default Recently bought a Dynatron SRX 80, need help with a few things!

Hey everyone!

I've bought myself a Dynatron SRX 80 for £20. Woodwork is in good nick, radio works good; as does the tape deck.

However, I have a few gremlins that are confusing to me as someone new to restoration!

Issue number one, the cartridge clips have come off of some of the wires. Are these easy enough to fix? I've read they just need soldering on, but just wanting to double check this is the case.

(It was my fauly in all honestly, I had the bottom of the cart was grinding upon a test record, so I went to re-align the cart and whilst doing so I took some of the wires off of the cartridge clips by accident. D'oh!)

Issue number 2, another reason I took the cartridge off was because of a buzzing sound I would occasionaly get whilst playing the test LP. I believed this was possible down to the cart not being wired up correctly. (Certainly isn't now, rofl.) Tape and Radio are buzz free.

Issue number 3, the right speaker that pulls out at the side is currently disconnected interally as the seller told me it was losely connected when he acquired it and wasn't working, so he just disconnected it and will need to be re-soldered. My plan is to attempt to re-solder this later tonight and hope for it works! On the occurance it does not, what else could I look into it being?

Issue number 4, sometimes when I turn it on, there is a loud pop through the speakers, only ever really quickly. May not be an issue, but I was wondering if anyone knows why it might do this? And where can I get an ariel for it from?

And lastly, is there any manuals for it that someone may care to share? I've searched and searched, but I can't find one anywhere online!

Otherwise, it all functions great, looks great and sounds phenominal with the 3 out of 4 speakers working

Any help is greatly appreciated it help bring her to full glory!

Pictures below of the deck and the tonearm with the cartridge clips off for reference.
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Old 2nd Sep 2020, 9:05 pm   #2
Edward Huggins
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

Just seen this - whatever you do, DO NOT solder any wires diectly to the cartridge. It will destroy it. Do you know the correct LH and RH connections for this?
I would not worry about the POP when switched on. This can be explained to you later if you wish. There should already be an internal FM dipole (aerial) fitted.
There are 4 speakers in the SRX80, 2 at the sides and 2 downward firing. If it's not working one one side it's unlikely to be a speaker fault. More likely the failure of one amplifier channel - a very common fault on these. That may be the reason the speakers on that side were disconnected by the previous owner.
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Old 2nd Sep 2020, 10:48 pm   #3
Mogga96
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

Hi Edward!

Thank you for the reply!

Yeah I did some research before deciding to try it, so I'm versed up on knowing not to do that. Yeah, I remember what order the connections where.

As for the aerial, that would explain why I was able to tune in Smooth Radio no problem. I wassn't sure if it needed one or not though; thanks for clearing that up! (Smooth tuned in really well and sounded really good too!)

The downward firing speakers work on both left and right sides. It's the side speaker on the right that pulls out which is not working and not currently wired up. The downward firing speaker is still connected, it's that speaker on the right that pulls out that is not connected.

Yeah the pop isn't majorly bad, I was just wondering about it haha. What is that all about?

What are the things to look out for that tend to go wrong with this model I have?
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Old 4th Sep 2020, 11:32 am   #4
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

The "pop" at switch is just a consequence of the way the amplifiers settle down as their power supply voltage rises at switch on. Most likely the output follows the fast rising supply initially hence the "pop" then settles back to its normal level as capacitors charge up to their normal operating outages.

It's annoying but not serious!
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Old 4th Sep 2020, 12:59 pm   #5
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

I suggest you check the continuity of the faulty side speaker's voice coil. If OK, check the capacitor that connects to it. If the speaker's voice coil is open circuit, you'll need a replacement of a similar size and impedance.
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Old 4th Sep 2020, 6:06 pm   #6
Mogga96
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

OK, so very happy update! Deck is operating fine! Took the platter off, carefully fed through more tonearm wire down the tone arm and soldered on some new cartridge clips!

Cartridge alignment is spot on, too.

Some of the speakers are however, blown so they're going to need replacing. But that's a job for another day, headphones for now!
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Old 4th Sep 2020, 9:20 pm   #7
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

Curiosity got the cat!

I took the torubled right speaker off at the side and that is now functioning! It turns out, it was a little block that had shifted, with contact pins that touch the prongs the wires connect to. Put that back in place and now the right pull out speaker works!

As for the blown speakers, they are the bass downward firing ones underneath.
I've took a picture of the number printed into one of them (Both sides have the same number), but googling to find the exact speaker is proving dificult!

So below attatched, is a picture of one of the blown speakers with the number printed on it, in hopes someone can help source a replacement!

She's getting there and it feels so rewarding!
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Old 4th Sep 2020, 9:29 pm   #8
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

It looks like the surround has disintegrated in that picture. If the voice coil is still intact you could probably get away with just buying a new surround and gluing it into place (after cleaning off all the remains of the old surround).
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Old 4th Sep 2020, 9:39 pm   #9
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

How can I tell if the voice coil is fine or not?

I've currently got it on now listening to the radio and it sounds fine; if I were to turn it up though there becomes buzzing. Which I'm going to guess is due to the surrounds?
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Old 4th Sep 2020, 11:22 pm   #10
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

Quote:
Originally Posted by Mogga96 View Post


How can I tell if the voice coil is fine or not?

I've currently got it on now listening to the radio and it sounds fine; if I were to turn it up though there becomes buzzing. Which I'm going to guess is due to the surrounds?
If the voice coil was open circuit, you wouldn't hear anything at all. Replace the speaker surround and I'm sure it will be fine. You'll need to do the other speaker as the likelihood is its gone the same way.
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Old 5th Sep 2020, 9:33 am   #11
Edward Huggins
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

I got the impression from your earlier Posts that it was only the RHS pull-out speaker that had failed? This type of Dynatron usually had 8" x 5" downward firing speakers, but yours looks round. I'm guessing its chassis diameter is 6.5". If you are daunted by the task of sourcing, then adhring the new surrounds and ensuring that the cone is centred, you can buy 2 new units. You will need to ensure that they are the the same impedence as the originals. They are likely to be 8 ohms, but they will need measuring first.
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Old 5th Sep 2020, 1:23 pm   #12
Mogga96
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

It had seemed so, till I got into the nitty gritty of looking at the internals.

The voice coils are fine though. So I might look to find surrounds and fitting them on. If I were to change speakers though, how would I wire them up? Might sound like a silly question, but on the original downward firing speakers, they have the two prongs on them. I've tried looking up speakers with them, but I can't seem to find any with that kind of fitment.

Yeah, they appear to be round; I can take one out and get a picture later tonight when my little one is in bed, if it helps to source replacements.

Thanks so far for all the input, it is greatly appreciated!
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Old 5th Sep 2020, 1:35 pm   #13
Edward Huggins
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

If you do buy new speakers, they will have 2 connecting tags on them so don't worry about that. You will need to carefully measure the existing cone diameter, so the speaker will need removing. You need to take into account the sourcing and cost of the surrounds as they will need to be exact. Then there is the task of fitting and centering them. Read up on this topic first. Search the Stickies above for previous repair experiences.
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Old 5th Sep 2020, 1:54 pm   #14
Mogga96
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

Ahh I see, thanks for the info!
I do have some Wharfedale Shelton XP2's sitting around that work great and sound incredible, this might be a sin, but I wonder if they'd be possible to strip down and install into the Dynatron.

Is there any speakers you'd suggest to replace the current ones with?
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Old 5th Sep 2020, 3:53 pm   #15
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

I would leave your Wharfedales as they are. No point in ruining such nice little speakers. To help you further we need to know the chassis (not the cone) diameter of the downward firing units and their impedance. This might be printed on the speaker's chassis. It will be something like 4 or 8 or 16 followed by the omega symbol.
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Old 6th Sep 2020, 7:04 pm   #16
Mogga96
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

Alright, so they're 6.5" in diameter (measured from one edge to another diagonally and across and both measure at 6.5").

I think I found the omhs rating, but it doesn't have an omega symbol, nor does it have ohms written, just a number followed by OH.

It's faded a fair bit too, so it's hard to read, so attatched is a picture. Is it 4, 5, 6, 8 or a 9? I don't have a multimeter or anything like that to test otherwise. Both speakers are like this. Also, below is a picture of the state the speakers are in.
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Old 6th Sep 2020, 8:09 pm   #17
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

It appears to be a Philips unit in a Dynatron cabinet: https://www.vintage-radio.net/forum/...d.php?t=106028
The speakers are most probably 8 ohm, those markings are production stamps.

https://www.worthpoint.com/worthoped...ayer-270772229
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Old 6th Sep 2020, 8:33 pm   #18
Mogga96
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

Interesting. I do have some 8 ohm Sony speakers of the same size, but the terminals are slightly different.

Here's the pictures I uploaded to my imgur account:
********************gallery/l3sNPhB
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Old 6th Sep 2020, 9:41 pm   #19
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

So I put the original speakers back in for now and connected them up as they were, now it doesn't power on anymore. Checked the back to see if any fuses had blown and I'm met with the below attatched image.

Is it dead?
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Old 6th Sep 2020, 11:15 pm   #20
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Default Re: Recently bought a Dynatron SRX 80, need help with a few things!

It doesn't matter if the speaker tags are in a different place as long as you connect then up the same way round. Have the fuses blown, can't tell from the photo. If so replace with the same values.
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