Dansette Bermuda MK II ?? - Page 7 - UK Vintage Radio Repair and Restoration Discussion Forum

Station X · 28th Feb 2018, 4:52 pm

By "No resistance" do you mean open circuit (infinite resistance) or short circuit (zero or very low resistance?

If in doubt check what the meter reads with the leads not touching (infinite resistance) and the leads touching (zero resistance).

Station X · 28th Feb 2018, 5:02 pm

Here's an extract from the Bush RP60 circuit which is very similar. It should make things easier as the valve pin numbering is clear.

The resitive path is:

pin 2
R9 180R (220R in the Bermuda)
R7 680k
R8 33
pin 3

Station X · 28th Feb 2018, 5:08 pm

Quote:

Originally Posted by ms660

The schematic plot so far, so far as I can make out.

Lawrence.

Not quite the same as the Bermuda or RP60 diagram, but regardless of which diagram is correct there should still be resistance between pins 2 and 3.

ms660 · 28th Feb 2018, 5:11 pm

The schematic plot so far, so far as I can make out.

Apologies for the re post, scanner missed a bit on the first one which has now been deleted, new scan copy enc.

Lawrence.

martinpinner · 28th Feb 2018, 5:14 pm

Just read post 119 again and set the meter higher and got a reading of 1055K

Station X · 28th Feb 2018, 5:26 pm

220 + 1,000,000 + 33000 = 1033220, so probably not too far off.

Station X · 28th Feb 2018, 5:39 pm

Quote:

Originally Posted by martinpinner

The 100K resistor is connected to pins 7 and 9 by the PCB board but has a reading of 140K. The volt measurements at both ends are 100 and 3.6.

Something is obviously pulling down pin 9 to near chassis voltage.

I'd suspect the two 0.01uF caps connected to pin 9. Try disconnecting one end of each of them then checking if the voltage at pin 9 rises.

martinpinner · 28th Feb 2018, 5:40 pm

Thanks for the schematic I will look at this tomorrow.
With regard to post 122 I do not have any resistors with a value of 680K

Station X · 28th Feb 2018, 5:43 pm

Quote:

Originally Posted by martinpinner

With regard to post 122 I do not have any resistors with a value of 680K

That's probably because your player is wired as per Lawrence's diagram and the 680k resistor is replaced by the 1M tone control.

martinpinner · 1st Mar 2018, 4:24 pm

I have just disconnected the sufflex capacitor from the PCB going to Pin 9. It is also connected to the PCB going to Pin 8. The volt reading on pin 9 is now 1.22. I have disconnected the other capacitor as I had already replaced this with a new one as recommended by Lawrence - it has a value of 0.0022uf.

Martin

Station X · 1st Mar 2018, 4:33 pm

Working from Lawrence's diagram in post #124, I can see no capacitor connected to pin 8 of the valve.

Try disconnecting the 100k resistor at the pin 9 end only. With power applied, do you now see a high voltage w.r.t chassis on the disconnected lead of the resistor?

ms660 · 1st Mar 2018, 4:46 pm

Quote:

Originally Posted by martinpinner

I have just disconnected the sufflex capacitor from the PCB going to Pin 9. It is also connected to the PCB going to Pin 8. The volt reading on pin 9 is now 1.22. I have disconnected the other capacitor as I had already replaced this with a new one as recommended by Lawrence - it has a value of 0.0022uf.

Martin

Out of interest, which capacitor in these photo's is the 0.0022uF you refer to above?:

https://www.vintage-radio.net/forum/...6&d=1519641417

https://www.vintage-radio.net/forum/...6&d=1519641417

Lawrence.

Station X · 1st Mar 2018, 4:52 pm

The picture in post #53?

Station X · 1st Mar 2018, 5:00 pm

This is confusing. I think the tone correction capacitor, which is wired directly on the transformer tags is supposed to be 0.0022uF rather than 0.0033uF.

Station X · 1st Mar 2018, 5:14 pm

I've printed out all the pictures now so I can study them side by side.

The other Sufflex capacitor which is terminated on the spare tags on the output transformer comes from pin 9 of the valve. From the output transformer it appears to go, via a blue wire, to the wiper of the tone control. This fits in with Lawrence's diagram.

martinpinner · 1st Mar 2018, 6:02 pm

Quote:

Originally Posted by Station X

I've printed out all the pictures now so I can study them side by side.

The other Sufflex capacitor which is terminated on the spare tags on the output transformer comes from pin 9 of the valve. From the output transformer it appears to go, via a blue wire, to the wiper of the tone control. This fits in with Lawrence's diagram.

This is correct.

I have disconnected the 100K resistor at the pin 9 end and taken a reading at the resistor end and it is 105 volts.

Station X · 1st Mar 2018, 6:07 pm

What's pin 2 reading now?

martinpinner · 1st Mar 2018, 6:09 pm

The sufflex capacitors changed are as per photo's
Photo 1 shows C7 0.0022uf
Photo 2 shows C5(vertical) 0.047uf and C6 (horizontal) 0.047uf

ms660 · 1st Mar 2018, 6:09 pm

Reconnect the resistor and disconnect one end of the capacitor that's connected between pin 9 and the 33k resistor and disconnect one end of the capacitor that's connected to the blue wire that goes to the tone control, then measure the voltages on pin 9, pin 3 and pin 2.

EDIT: Post crossed.

Lawrence.

Station X · 1st Mar 2018, 6:32 pm

Yup. Something connected to the track going to pin 9 is pulling down the voltage. I doubt it's the valve, so that leaves the two capacitors which Lawrence and I suggested be disconnected.

Or perhaps some other component has been erroneously connected to the track going to pin 9?

28th Feb 2018, 4:52 pm	#121
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Dansette Bermuda MK II ?? By "No resistance" do you mean open circuit (infinite resistance) or short circuit (zero or very low resistance? If in doubt check what the meter reads with the leads not touching (infinite resistance) and the leads touching (zero resistance). __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

28th Feb 2018, 5:02 pm	#122
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Dansette Bermuda MK II ?? Here's an extract from the Bush RP60 circuit which is very similar. It should make things easier as the valve pin numbering is clear. The resitive path is: pin 2 R9 180R (220R in the Bermuda) R7 680k R8 33 pin 3 Attached Thumbnails __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

28th Feb 2018, 5:11 pm	#124
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Dansette Bermuda MK II ?? The schematic plot so far, so far as I can make out. Apologies for the re post, scanner missed a bit on the first one which has now been deleted, new scan copy enc. Lawrence. Attached Thumbnails

28th Feb 2018, 5:14 pm	#125
martinpinner Hexode Join Date: Oct 2015 Location: Sheffield, South Yorkshire, UK. Posts: 252	Re: Dansette Bermuda MK II ?? Just read post 119 again and set the meter higher and got a reading of 1055K

28th Feb 2018, 5:26 pm	#126
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Dansette Bermuda MK II ?? 220 + 1,000,000 + 33000 = 1033220, so probably not too far off. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

28th Feb 2018, 5:40 pm	#128
martinpinner Hexode Join Date: Oct 2015 Location: Sheffield, South Yorkshire, UK. Posts: 252	Re: Dansette Bermuda MK II ?? Thanks for the schematic I will look at this tomorrow. With regard to post 122 I do not have any resistors with a value of 680K

1st Mar 2018, 4:24 pm	#130
martinpinner Hexode Join Date: Oct 2015 Location: Sheffield, South Yorkshire, UK. Posts: 252	Re: Dansette Bermuda MK II ?? I have just disconnected the sufflex capacitor from the PCB going to Pin 9. It is also connected to the PCB going to Pin 8. The volt reading on pin 9 is now 1.22. I have disconnected the other capacitor as I had already replaced this with a new one as recommended by Lawrence - it has a value of 0.0022uf. Martin

1st Mar 2018, 4:33 pm	#131
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Dansette Bermuda MK II ?? Working from Lawrence's diagram in post #124, I can see no capacitor connected to pin 8 of the valve. Try disconnecting the 100k resistor at the pin 9 end only. With power applied, do you now see a high voltage w.r.t chassis on the disconnected lead of the resistor? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

1st Mar 2018, 4:52 pm	#133
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Dansette Bermuda MK II ?? The picture in post #53? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

1st Mar 2018, 5:00 pm	#134
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Dansette Bermuda MK II ?? This is confusing. I think the tone correction capacitor, which is wired directly on the transformer tags is supposed to be 0.0022uF rather than 0.0033uF. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

1st Mar 2018, 5:14 pm	#135
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Dansette Bermuda MK II ?? I've printed out all the pictures now so I can study them side by side. The other Sufflex capacitor which is terminated on the spare tags on the output transformer comes from pin 9 of the valve. From the output transformer it appears to go, via a blue wire, to the wiper of the tone control. This fits in with Lawrence's diagram. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

1st Mar 2018, 6:07 pm	#137
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Dansette Bermuda MK II ?? What's pin 2 reading now? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

1st Mar 2018, 6:09 pm	#138
martinpinner Hexode Join Date: Oct 2015 Location: Sheffield, South Yorkshire, UK. Posts: 252	Re: Dansette Bermuda MK II ?? The sufflex capacitors changed are as per photo's Photo 1 shows C7 0.0022uf Photo 2 shows C5(vertical) 0.047uf and C6 (horizontal) 0.047uf Attached Thumbnails

1st Mar 2018, 6:09 pm	#139
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Dansette Bermuda MK II ?? Reconnect the resistor and disconnect one end of the capacitor that's connected between pin 9 and the 33k resistor and disconnect one end of the capacitor that's connected to the blue wire that goes to the tone control, then measure the voltages on pin 9, pin 3 and pin 2. EDIT: Post crossed. Lawrence.

1st Mar 2018, 6:32 pm	#140
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Dansette Bermuda MK II ?? Yup. Something connected to the track going to pin 9 is pulling down the voltage. I doubt it's the valve, so that leaves the two capacitors which Lawrence and I suggested be disconnected. Or perhaps some other component has been erroneously connected to the track going to pin 9? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.