Argyll Minor reel to reel help needed.

[sobell1980]

Good morning all.
This is a first for me to repair one of these. This has been given to me to repair by my friend who picked it up on holiday. All the mechanics work ok, it fast forwards and rewinds and plays a tape that came with it all but very quietly on max volume. It could be that the tape was recorded on a low level, maybe or the heads need cleaning. However, I've removed the chassis this morning and there are wax and hunts caps fitted, the Hunts cap has cracked up and the value has fallen off so I need to know what to replace it with but I can't find a diagram. I've downloaded the BSR TD2 trader sheet but it contains no wiring info or electrical component info. Can anyone supply a diagram? or be able to tell me where I can find one? The trader sheet will be useful for servicing the mechanical parts as I can certainly see dried grease that will cause future issues.
Also can anyone tell me, are the cassettes that hold the tape all the same size? I need to source a known good tape to test this. The tape with it does not look great and I don't know at what recording level it was recorded at so could cause me to chase my tail. Any advice greatly appreciated. I've restored BSR decks previously a Beogram 1000 and numerous valve radios. I'm aware of the dangers etc and only excersise good safe working practices.
Many thanks.
Dave.

[sobell1980]

Some pictures which will hopefully help.

[ms660]

http://www.service-data.com/section....1/argyll-minor

Lawrence.

[sobell1980]

I've snipped the Hunts cap out of circuit to measure it's value on the meter. It's a Hunts AD51 350V YDH. SEE PICS.
It measures approx 0.5 uF on my meter . If you look at what remains of the value marking on the cap it could read 0.1uF as you can just make out the top of the letters uF. In which case my meter is measuring a 0.1 uF that's gone higher in value?

[AC/HL]

You'll probably find that all the paper capacitors are leaky, which gives high capacity readings. There's not a lot of point in measuring them, they will need replacing. As long as there are no major items faulty, there's a good chance that this will restore performance.

[Nuvistor]

The reels of tape have different reel sizes, I think the largest size that your deck takes is 5 inch or thereabouts, the sizes are standard. The central hub is a standard fitting.

See this post for possible sources http://vintage-radio.net/forum/showthread.php?t=55199
you will require a take up spool if you don't have one.

Frank

[Nickthedentist]

The TD2 takes reels of maximum diameter of 5 3/4" ISTR.

Nick.

[yestertech]

Dave
There should be quite audible/hum and noise with the machine set to replay and no tape passing the head. If the recording that came with it was made at low level, then you'd still expect to hear lots of tape noise as it passes the heads unless they're very caked with oxide.
You'd still hear the replay noise though.
If neither of these are present, then suspect the electronics:

Low HT is possible, especially if it has non-valved rectification.
Low gain could also be due to an anode load going high.
Generally every drop of gain is squeezed from as few valves as possible on these cheap machines, so a fault reducing the gain slightly will make a big difference.
if the replay background noise is generally quiet, it probably won't be the tape but it won't hurt to give the heads a good clean with isopropyl alcohol for starters.

Other possibilities are dirty contacts on the dreaded record/replay switch. Some of these can be a pain with multiple contacts, as so many things are switched back and forth between the two modes, again to reduce the valve count.

You'll sort it !

Andy

[julie_m]

I spy what looks like a Siemens half-wave Selenium rectifier on the left-hand end of the "bulkhead" in photo 4. This could well have gone high-resistance. Measure the HT. If in doubt, try a diode with a series resistor of about 270Ω, 3W to begin with and work up or down to get the HT within 10% of what is marked on the wiring diagram.

[sobell1980]

Thankyou all for your replies. I will check the high and low tension after the suspect caps have been changed.
I still, for the life of me can't find or correspond that cracked Hunts cap to the wiring diagram. One end of the cap is connected to one of the wires coming from the erase head. There are two wires coming from the erase head. One terminates at the earth point on the PCB. The
Other wire of the erase head connects to a point on the pcb where it then connects to this large Hunts cap. For the life of me I can't see it on the diagram. It should connect straight to the bottom of L1 I believe but it goes through this huge cap first. The location of components is of no use either as the lay out on the circuit board is different on mine to that of the diagram. For a start it shows the valve sockets mounted on the chassis, I just have two holes in the chassis, the valves on mine are mounted on the PCB. So none of the components in that area on the PCB relate to the trader sheet. It's purely because I like to understand and follow the circuit and not just replace components on a whim (even though I know they need changing ). The value has cracked off this cap so I have no idea what to replace it with other than locating it on the diagram where it connects directly to one side of the erase head.
If I follow the diagram for the recording, playback head I can easily follow it and it corresponds to the circuit diagram. I had to walk away from it yesterday as I had driven myself mad with it. Many thanks for your help and previous replies.
Dave.

[sobell1980]

Picture of the area of confusion /concern.

[llama]

I wonder if member Ti Pwun can help. He has been asking for dud Hunts caps to scan so if he has acquired an AD51 that is 350 V and exactly the same length as yours that'll give you a match for the value.
Graham

[julie_m]

Just try 100 nF for now. It'll probably work

[Nickthedentist]

Errors on circuit diagrams, and undocumented circuit revisions aren't uncommon, and as Julie says, absolute values are generally not critical in machines like this.

[sobell1980]

Many thanks as always for your guidance and putting my mind at rest with this. You are right, I think the circuit has been modified without documenting it. Going back to it and going over it again it would appear the only difference in the diagram with this additional cap is that it is fitted in series between the top of the erase head and the junction of c17 and C18 where these two caps meet.the rest of the PCB can be compared to the circuit diagram from c17,C18 and L1 junction point all makes sense. So it's purely a case of a cap has been added between here and the erase head.
I'm going to fit a 0.1uF cap . I think by looking of what remains of the letters printed on the cap, this is most likely what the value would have read before its insulation broke away. I shall carry on replacing all the waxes and paper caps and let you know the outcome. Their is no hum present so I'm going to leave the large electrolytics be. Hope to get this done on Sunday afternoon. Life and work seem to have taken over the last few months not leaving much time for my hobbies do hopefully Sunday will bring some progress.
Many thanks.
Dave.

[AndiiT]

Hi,
Your Argyll Minor looks like it may be a "late" model hence the PCB circuitry and circuit modifications. A BSR 222 passed through my hands some time ago which was very similar to the Argyll Minor and from memory almost identical internally to the pictures that you have posted of your model.

Before getting too excited however there is probably no information available for the BSR models as I suspect that they were "catalogue specials"

It might help though to take a look at the Fidelity Playmaster circuit as they were PCB based and the basic circuitry was vey similar to the Argyll Minor anyhow, particularly the amplifier and erase/bias oscillator sections.

Regards

Andrew

[sobell1980]

Many thanks, Andrew. I have now downloaded the Fidelity Playmaster circuit and all is much clearer including the locations of components are accurate to what's in front of me.
I recapped the set and tried a switch on. Nothing, not even on full volume could it be faintly heard. I removed the chassis and the valves are all stone cold.
It was then I noticed I had created a short with a bit of solder across the circuit board. The short was between pin 6 (anode) and pins 4 and 5 (heaters) of valve 1 the Ecc83. Now whether this did or did not actually create a short I don't know but I imagine it won't have done the heaters or valve much good. I removed the short, switched on and still no good. Valves stone cold.
I checked the anodes of valves 1 and 3. Both receiving HT all but it being too high because nothings happening with the valves. I then checked my heater ac voltage. From the mains transformer i have 7.5 volts ac reaching the circuit board on a pair of wires. However measuring across pins 4 and 5 of valves 1 and 3 I'm only getting 3.7 volts ac. Surely I should be getting the 7.5 v ac ? On valve 1 the Ecc83 I can measure from pin 4 or 5 to heater centre tap pin 9 and still get 3.7v ac. Is this right ? Or am I measuring it incorrectly? The circuit quotes 6.3 v ac from the mains transformer. I'm only getting half of the quoted ac st the heaters? I've measure the valve heaters and the are showing continuity across the heaters. So I'm a little stuck. Any offerings of where to go greatly received.
Ive been through all my valves and have no substitutes.
Many thanks.
Dave.

[sobell1980]

If anyone has or can give any further input on my last post #17 I would be most grateful. The service data quotes 6.3v to from the mains transformer. However it doesn't quote the actual measurementioned at the heater pins. I'm getting 7.5 v ac on a pair of wires from the mains transformer which terminate at the pcb. But measuring my voltage on the valve heater pins I'm only receiving 3.7 v ac. One of the pairs of wires that delivers the 7.5 v ac goes to the heaters of v1 pins 4 and 5 and the other goes to the heater of v3 pin 4 . Would this explain why I get the 3.7v ac to each valve heater and nor the 7.5v ac where the pair of wires meets the pcb? As I said in my previous post that the short I created and then found may or may not have put HT directly to the valve heaters. However I have measured the heaters continuity on valve 1 and I get approx 13 ohms across both its heaters and approx half of that from each heater pin to the heater pin centre tap on pin 9. On valve 3 I get approx 1 ohm across its heater. Even though I'm getting continuity across the heaters of the valves is it still possible I've destroyed them with this short? Or is it my heater voltages incorrect? Hope someone can help and advise? Many thanks.
Dave.

[ms660]

I don't have the schematic, I'm assuming that one of the heater feeds is connected to HT-ve (chassis/ground) if that's the case then clip one meter probe to that connection where that feed from the transformer joins the PCB then probe the voltage in the circuit from the other PCB connection that connects to the mains transformer through to the valves, if the feed to the heaters is via PCB tracks then check for cracks in the PCB and dry joints etc.

Lawrence.

[julie_m]

Looking at the Argyll Minor and later Playmaster circuits, the heater winding has a centre tap which is connected to 0V. So each end of the heater transformer will be at 3.15 V AC with respect to chassis.

Also, don't forget that when an ECC83 is being used on a 6V3 heater supply, the heater connections are (pins 4 and 5 together) and pin 9.