Sony 2010 FET mod
NiteCapt
protect my Sony 2010 from static discharge? I understand it's been posted
somewhere but I dont know where to find it. I'd like to protect it from damage
as I have it hooked up to a longwire.
Thanx
RVP
rah...@acm.org
If anyone knows this, or has a reference, please post it
here.
In a side-by-side comparison my 2010 has about 20% of the
signal strength of an identical unit. I suspect I'm a
victim of the FET problem.
Is this an easy repair? How much does Sony charge to do it?
John R. Cope
HOW TO DETECT AND REPAIR THE
COMMONLY BLOWN TRANSISTOR IN THE SONY 2010
Michael Covington, N4TMI
(Free distribution; you are welcome to copy and distribute
this document.)
As is well known, transistor Q303 in the front-end of the Sony ICF-2010
general coverage receiver is easily damaged by static electricity.
Here is information on how to diagnose and fix this problem.
WHAT ARE THE SYMPTOMS?
A 10- to 20-dB loss of sensitivity on AM (longwave, medium wave, short
wave). If you have a good antenna you may not even notice the loss.
In all other respects the radio functions normally.
In all other respects the radio functions normally.
HOW DO I TEST IT?
If you buy a used 2010 it's a good idea to perform this test even if you
do not notice a performance problem.
Remove the back cover and locate transistor Q303, near the antenna input.
Identify its three terminals (D, G, and S).
Now measure the voltage from each of those terminals to ground, with the
receiver turned on and receiving shortwave. (A convenient ground connec-
tion is the outer part of the antenna jack.)
The voltages should be: S 0.2V G 0.0 V D 2.9 V
Note especially the drain (D) voltage. If it is substantially lower than
2.9V, the transistor is leaky. (Mine measured 1.6V when defective.)
If it's substantially higher (like 4.5V), the transistor is open.
2.9V, the transistor is leaky. (Mine measured 1.6V when defective.)
If it's substantially higher (like 4.5V), the transistor is open.
HOW DO I FIX IT?
The popular MPF-102 transistor, available at Radio Shack, is a suitable
replacement. (Sony used a 2SK152, not widely available in the U.S.A.)
Simply unsolder the old transistor and install the new one, then check
voltages again. No alignment is necessary.
HOW DO I PREVENT FURTHER TROUBLE?
By connecting the shortwave antenna through a protective diode network,
as shown below.
\|/ Antenna
|
+-----------+--------+----------------------------> tip of plug
| |
?
+-----------+--------+----------------------------> tip of plug
| |
\ / --- Sony 2010
--- / \ Four 1N914 or antenna
| | 1N4148 diodes jack
\ / --- (do not substitute)
--- / \
| |
+-----------+--------+----------------------------> sleeve of plug
|
-------
-----
--- Ground (optional)
The diodes limit all voltages going into the receiver. Use the
specified types; other kinds would produce loss of signal, signal
mixing (resulting in image frequencies), or both.
The 2010 has a built-in protective diode network connected to the
?
The 2010 has a built-in protective diode network connected to the
built-in telescoping antenna but not the antenna jack.
David Atkins
>In a side-by-side comparison my 2010 has about 20% of the
>signal strength of an identical unit. I suspect I'm a
>victim of the FET problem.
>
>Is this an easy repair? How much does Sony charge to do it?
Do it yourself. Use a MPF-102 (even Radio Shack, or a REAL electronics
store) to replace your dud 2SK152 if you can't get hold of the original
type.
You can test your existing FET with a voltmeter. You should expect to
get:-
G 0v
D 2.9v
S 0.2v
An open transistor will have the Drain at 4.5v. A leaky one will be
considerably lower than 2.9v
When it is done, protect the external antenna input with four 1N914 or
1N4148 diodes arranged in two back-to-back series pairs ( two diodes in
series, back-to-back with two diodes in series)
Much cheaper than the postage, let alone the price Sony charges :-)
--
David Atkins
Reprint Manager
Medium Wave News
rah...@acm.org
spec". The repair takes "no more than two weeks."