![]() |
![]() |
![]() |
|
Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
![]() |
|
Thread Tools |
![]() |
#41 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
Graham just one thing .Do i check these readings from under the chassis with the valve in situ . Or do i pull the valve out of its holder and put the test probe of the meter in the holes showing. I removed the valve to test the pin outputs going anti clockwise . .No one said , or told me to do it i just thought it was from above
|
![]() |
![]() |
#42 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 14,285
|
![]()
If you're measuring voltages you need to have the set switched on and the valve in its socket.
If you're measuring resistances you need to have the set switched off. In this case it won't matter whether the valve is in its socket or not. It's obviously easier to check the cathode resistor by removing the valve and connecting your meter between chassis and pin 2. As you say when looking form above the pins number anti-clockwise.
__________________
Graham. Forum Moderator Keep the soldering iron hot. |
![]() |
![]() |
#43 | |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]() Quote:
|
|
![]() |
![]() |
#44 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
So i did that right .From above with valve out anticlockwise . Pin 5 = 210 volts this is ok ? and pin 1= 2 volts . . Talk later on about next step.
|
![]() |
![]() |
#45 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 14,285
|
![]()
2 Volts on pin 1 is bad. It'll be caused by C34 being electrically leaky. Disconnect one end of C34 and check pin 1 again. If the reading has dropped to close to zero C34 is the problem and needs replacing.
The is the same problem I had with my set. https://www.vintage-radio.net/forum/...d.php?t=127728
__________________
Graham. Forum Moderator Keep the soldering iron hot. |
![]() |
![]() |
#46 | ||
Pentode
Join Date: May 2010
Location: Wick, Scotland, UK.
Posts: 134
|
![]() Quote:
The mods of 1971 radio mags greatly improved these sets. Fit the voltage stabilizer, improve the vfo stability. control of Rf stage etc. |
||
![]() |
![]() |
#47 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
Graham just returned from the weekly shoping trip .And i have a cold but i had to go out . And my friend next door has his wife bed ridden and not well enough himself so i do his shoping as well. Therfore i had no option but to go .
I see the C34 on the map lol [ schematic diagram ] so i will remove the bottom cover and then disconnect one side of it . Then come back with the news Wednesday.Your a star Graham ... |
![]() |
![]() |
#48 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
Thank you James for that information . And all the valves have been replaced the last 2 yesterday . No change .Even changed ext speaker in case it was faulty.
Going back to Graham . Last night i removed the bottom of the receiver but looking in at the base of v8 i can see no C34 i took pictures to post up but i am not able to do that on the forum .Are these C34 about the size of a 1p and coated ? The schematic shows 4 C3-s i can see none of them at all on the base of v8 . |
![]() |
![]() |
#49 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 14,285
|
![]()
I think you'll find that as this set uses a Printed Circuit Board (PCB), C34 is mounted on the same upper side of the PCB as the valve. However it will have to be unsoldered by melting the solder on the lower side of the PCB.
Give me a bit of time and I'll take a picture of the repair I made to my own set. EDIT. Would you believe I still have the faulty capacitor C34? It is grey 16mm long, 8mm diameter and has .01 uF written on it. FURTHER EDIT. If you look in the service manual you'll find a drawing showing the layout of the components on the PCB. C34 is clearly shown.
__________________
Graham. Forum Moderator Keep the soldering iron hot. |
![]() |
![]() |
#50 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
Top marks Graham . Yes i was looking in the wrong place ,as you say its sited on the top side next to the valve V8 reads 0.01 uf [M] 600 wv is this the one ? looks like there are 4 of them the one you talk about and thee smaller ones .
|
![]() |
![]() |
#51 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 14,285
|
![]()
That's the one! Made by RightCon Japan.
__________________
Graham. Forum Moderator Keep the soldering iron hot. |
![]() |
![]() |
#52 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
Graham looking in the schematic the values they are 25 wv a 150wv and 400wv and last one is 600 wv . Then looking at the schematic the C34 is 0.01uf 20 % + or - the one i am looking at is 25 wv .
|
![]() |
![]() |
#53 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 14,285
|
![]()
The capacitor you have to disconnect is C34. Its capacitance is .01uF and its working voltage (WV) is 600V. Mine is actually 630 WV, but it doesn't matter.
You clearly identified it in post #50.
__________________
Graham. Forum Moderator Keep the soldering iron hot. |
![]() |
![]() |
#54 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
Graham not questioning your knowledge but if you have your schematic .Could you just check .Mine reads in the service manual that C34 is 25 WV why is there no value only 25 % + or WV - ? Trev
|
![]() |
![]() |
#55 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 14,285
|
![]()
I've looked at the service manual.
In the parts list is doesn't actually give a working voltage for C34. It says it's a 0.01uF with a tolerance of plus or minus 20%. The circuit diagram simply says C34 0.01. The PCB layout says C34 .01. The component itself is labelled CP-C .01uF (M) 630WV RightCon Japan There is no conflict between any of the above values.
__________________
Graham. Forum Moderator Keep the soldering iron hot. |
![]() |
![]() |
#56 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
So next step Graham is to temove that 600wv capacitor . Jusr doublechecked and it is showing 2 volt steady fron pin one ant /c . Come back later after i remove this capacitor from one side .
|
![]() |
![]() |
#57 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
So another way to identifie this is its the highest value being 600wv .Thank you back later on after its removed on one side .
|
![]() |
![]() |
#58 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 14,285
|
![]()
I've emailed you a copy of the service manual so that we can be certain that we're both singing from the same hymn sheet.
The capacitor to disconnect is that which I described in some detail in post #55.
__________________
Graham. Forum Moderator Keep the soldering iron hot. |
![]() |
![]() |
#59 |
Pentode
Join Date: Aug 2010
Location: Bewdley, Worcestershire, UK.
Posts: 184
|
![]()
Graham succsess , it now shows zero voltage at pin one ,I will remove the capacitor eventual,ly and replace it with another one .Looking on ebay i see nothing with the same value, would you have info on the location of one of these capacitor. I looked on cpc only to find hundreds and its confusing and not easy to choose the right part .Thank you for the step by step tuition .I might just get this sorted with your help.
|
![]() |
![]() |
#60 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 14,285
|
![]()
PM me your address and I'll send you a replacement cap FOC. It's the easiest way to go.
__________________
Graham. Forum Moderator Keep the soldering iron hot. |
![]() |