F5DQK jan 2008, rel 02 1
TE-1452G 144 MHz, 400W solid state amplifierrepairings & modifications
F5DQK jan 2008, rel 02 2
Réparation d’un ampli VHF TE-Systems 1452G
- Ampli reçu en état de marche , mais au contraire des marques concurrentes ne « digérant »pas plus de 25 Win …ATTENTION et PRUDENCE !!!!- A la suite d’une fausse manipe (entrée micro de l’IC-706MKIIg oscillant facilement), les 5 transistors ont rendu l’âme en un rien de temps !- Au contraire des marques concurrentes (Mirage, RFC, Tokyo Hy Power, etc.. AUCUNE PROTECTION du constructeur n’est prévue en cas de puissance excessive sur l’entrée RF, et de sortie avec TOS prohibitif !!- Platine epoxy commune aux versions 50, 144 et 432 MHz pour Pout>200W
Ce PPT illustre les faits suivants:
- Subtitution des 5 transistors MRF247 et précautions à prendre- Correction des nombreuses erreurs du schéma de principe (voulues par le constructeur)- Addition d’un fiche PTT Cinch RCA pour être en phase avec la concurrence- « Strap » du transistor driver permettant une Pin maxde 60W au lieu de 25W et autorisant ainsi l’emploi de tout TRx moderne. Correspond à la version TE 1454G- Mesures RF Pout fonction de Pin AVEC et SANSdriver.
Améliorations apportées:
- Alimentation +12V pour préampli de mât directement à TRAVERS de l’ampli (fini le sequencer)- Meilleurs circuits de linéarisation (prochaine modification)
F5DQK jan 2008, rel 02 3
- CAUTION: original version with driver doesn’t accept more than 25Win- The IC-706MKIIg mike input is very RF sensitive … and’d QRT the 5 x MRF247- Absolutely no Rf in overload or Rf out protections !!!
TE-1452G AS RECEIVED FROM UK
F5DQK jan 2008, rel 02 4
Repairing & modifications steps- Substitution of 4 times MRF247 in both parallel final stages & the MRF247 driver- Bypassing the driver with a coaxial cable allowing now 50 to 60W in = TE-1454Gwith reverse possibility to use the driver again (only allowing 15W max input)- PTT socket addition (RCA type)- Schematic mistakes corrections- Direct DC feeding compatibility addition for mast preamps (no more sequencer…)- Better biasing circuit (in a nearest future)
First note
TE-1452G printboard
Mother printboards on TE 0552G, 1452G and 4452G models with Pout>200W are exactly the same (also RA versions)
- CAUTION: original version with driverdoesn’t accept more than 25Win- Despite of other brands like Tokyo Hy Power, Mirage or RF Concepts, TE-Systems amps have absolutely no Rf in overload or Rf out protections !!!- The IC-706MKIIg mike input is very RF sensitive … and’d QRT the 5 x MRF247
F5DQK jan 2008, rel 02 5
TE-1452G printboard before repairing
F5DQK jan 2008, rel 02 6
TE-1452G schematic
Many errors in the initial scheme !
F5DQK jan 2008, rel 02 7
TE-1452G printboard after repairing
Substitution possible only after desoldering all previous metal clad mica capacitors on base and collector sides
Little teflon coax for driver bypassing
F5DQK jan 2008, rel 02 8
TE-1452G : driver cap position on base side
After repairing
Min distance ! Not optimized
Normal target (other new amp)
10 pF ?
F5DQK jan 2008, rel 02 9
TE-1452G : final cap position on base side (1 of 4)
After repairing
Min distance ! Not optimized10 pF ?
Normal target (other new amp)
F5DQK jan 2008, rel 02 10
TE-1452G : one final stage after repairing
10 pF ?
40 pF ?
1 nF
40 pF ?
F5DQK jan 2008, rel 02 11
TE-1452G : driver changed but « passed through »
- more RF input power (>50W instead of maximum 25W)- no more transistors overloading & shutdown- possibility to connect the driver again as formerly (+ collector & base DC inputs)
10 pF ?
40 pF ?
10 pF ?
Little teflon coax for driver bypassing
F5DQK jan 2008, rel 02 12
TE-1452G : DC bias
Ic=100 mA
Ic=100 mA per transistor
DRIVER39Ω, 10W 3.3Ω, 0.5W
FINAL
6.8Ω, 1W
50Ω, 5W
1N9001
F5DQK jan 2008, rel 02 13
Initial bias switching
Mod bias switching allowing now direct masthead preamp feeding with IC-910H or FT-736r rig
- Guardian 1st contact used both for Rfin and DC biasing injection
- DC biasing is now given by a 2nd separate relay- Guardian relay contacts only used now for RF switching
+12V DC in Rx position always present on all collectors & circuitry, except for the DC biasing
TE-1452G : mods for mast preamp DC feedthruBefore
After
F5DQK jan 2008, rel 02 14
DC on Guardian relay in Tx mode
GND
DC for preamp
Preamp & TRx relais DC feeding
RFout
RFin
TE-1452G : mods for mast preamp DC feedthru
F5DQK jan 2008, rel 02 15
DC bias feeding with RF shoke between RFin and TRx relay
input (under VOX_PTT printboard)
Rfin cap (must be taken off)
1nF cap (must be taken off & placed between collectors
and Relay RF output)
RFin
RFin
RFoutBefore
After
DC thru
1 nFa/ DC feedthru for masthead preamp direct feeding
TE-1452G : mods for mast preamp DC feedthru
F5DQK jan 2008, rel 02 16
2nd DC shoke (DC bias extracting)
+12V preampPTT line
Rx +12V Tx 0V
From +12V switch amp on
+12V DC bias whith
Txing
50 Ohm RFin line + DC bias
GND
TE-1452G : mods for mast preamp DC feedthru
Before After
Now DC biasing injection from the rig to the masthead preamp is possible
b/ DC bias separation from RF
Separated bias relay
F5DQK jan 2008, rel 02 17
TE-1452G: on board GaAs preamp
Preamp RFout & +12VAmp in
Preamp RFin
Amp out
F5DQK jan 2008, rel 02 18
TE-1452G : mods for mast preamp DC feedthru
Before After
c/ Separate preamp DC feeding
DC shoke (preamp DC bias feeding)
DC shoke : 1 pin desoldered
Added DC wire soldered now to
relay feeding
F5DQK jan 2008, rel 02 19
TE-1452G: on board GaAs preamp
Preamp out & +12V DC feeding shoke
7805
LCin
Autopolar Radj for Vsource =1V
Vd Radj
LCout
Preamp in + DC shoke
Top view
Gate
Drain
Desolder here
F5DQK jan 2008, rel 02 20
TE-1452G: on board GaAs preamp
Bottom view
RF protection with 2 diodes in each transistor
2 CMS caps for GaAs source RF biasing
+12V & preamp RF out
Preamp in & DC shoke
F5DQK jan 2008, rel 02 21
TE-1452G : mods for mast preamp DC feedthru
d/ Gain / Nf measures
Insertion losses Preamp meas
HP-8970a noise / gain analyser + Ailtech 7615 noise generator
F5DQK jan 2008, rel 02 22
TE-1452G : VOX scheme
Too high resistor, half value is sufficient
F5DQK jan 2008, rel 02 23
TE-1452G : VOX & PTT printboard mod
To TRX Guardian relay
GND
22 kΩ in parallel to the 1st one
Initial DC biasfeeding coil BEFORE Guardian TRx relay
With 11 kΩ, the VCE sat in the relay PNP transistor is now 1.5V instead of 4V initially !!
Bottom position
F5DQK jan 2008, rel 02 24
TE-1452G : rear of front panel
TE 1406 printboard
F5DQK jan 2008, rel 02 25
TE-1452G : adding of PTT cinch socket on rear panel
+12V arrival
- The initial remote accessory socket in normal & G versions has no utility- every other brand has a PTT cinch connector
F5DQK jan 2008, rel 02 26
TE-1452G : printboard connectors pin layout
1 2 3 4 56 7 8 9 10
1 2 3 4 56 7 8 9 10Front panel with switches & LEDs
Rear panel with RF in/out connectors
Output J3 remote plug10
General +12V incoming9
+12V after thermal security8
Preamp & LED switch7
Ground6
NC5
PTT or remote LED4
+12V after amp on switch beforethermal security
3
DC bias & RF LED2
FM/SSB switching1
On/off connector 1 nearfront panel
J3 SSB delay pot10
PTT from 4 conn 19
FM/SSB switching from 1 conn 18
+12V from 3 conn 17
Output on J36
Output LED to 7 on J35
Ground4
DC bias output3
Guardian TRx relay2
Preamp relay 1
RF switching connector 2 near rear panel
F5DQK jan 2008, rel 02 27
TE-1452G : J3 remote plug
LED cntrl gnded7
Ground6
PA cntrl gnded5
Preamp4
+12V, max 1A3
PTT2
FM/SSB1
J3 remote plug
J3 connector(not used in RA version)
Cinch PTT connector
+12V arrival
1
7 6 5 4 3 2
F5DQK jan 2008, rel 02 28
TE-1452G: RF power measures
F5DQK jan 2008, rel 02 29
0.6750.6700.6500.6250.626VBE (V)
8
12.5V
14
13V
33
13.8V
30
13.5V
4.5Ib bias (mA)
12V
TE-1452G biasing current
MRF247 driver
0.6620.6470.6350.6130.592VBE (V)
0.7
10
12.5V
2.22.01.90.4Ic total (A)
22
13V
75
13.8V
48
13.5V
6Ib bias (mA)
12V
4 x MRF247 final stages
F5DQK jan 2008, rel 02 30
TE-1452G: Pout versus Pin à 144.400 MHz without driver
35.833031029027745
35.833031029027740
39.1
34.2
31.9
29.8
27.3
24.4
21.5
16.5
14.4
I à 13.8V (A)
350
305
277
250
212.5
175
132.5
75
56
13.8V
52.55047.53.25
200182.517520
230225212.525
260250232.530
305
275
150
115
65
12.5V
68605
1225.11010
162.514015
325
282.5
13V
282.5
262.5
12V
50
35
Yield
%
Pin (W)
- Rig IC-706MKIIg, Pin from 3.2 to 50W- Wattmeter Telewave model 44A- Dummy load BIRD Termaline 8135 - 150W- MAAS SPS9600 power supply à 13.8V
=TE 1454G=TE 1454G
F5DQK jan 2008, rel 02 31
TE 1452G without driver at 144.35 MHz: Pout/Pin
50
100
150
200
250
300
350
0 10 20 30 40 50Pin (W)
Pou
t(W)
10
20
30
40
50
60
70
Pout (W) à 12V
Pout (W) à 12,5V
Pout (W) à 13V
Pout (W) à 13,8V
I (A) à 13,8V
I (A
mps
)
U=13.8V
Pin allowed now up to 60W
I @ U=13.8V
=TE 1454G=TE 1454G
U=12V
F5DQK jan 2008, rel 02 32
35.855.1854.4246.53
35.855.1854.4246
39.1
34.2
31.9
29.8
27.3
24.4
21.5
16.5
14.4
I à 13.8V (A)
55.44
54.84
54.42
53.98
53.27
52.43
51.22
48.75
47.48
13.8V
46.7735.12
52.4343
53.2743.98
53.6644.77
47.7837
50.4140
51.4641.76
54.51
54.19
12V
46.99
45.44
Pin dBm
- Rig IC-706MKIIg, Pin from 3.2 to 50W- Wattmeter Telewave model 44A- Dummy load BIRD Termaline 8135 - 150W- MAAS SPS9600 power supply à 13.8V
=TE 1454G=TE 1454G
TE-1452G: Pout versus Pin à 144.400 MHz without driver
F5DQK jan 2008, rel 02 33
TE 1452g without driver à 144 MHz: Pout/Pin
46
47
48
49
50
51
52
53
54
55
56
35 37 39 41 43 45 47 49Pin (dBm)
Pou
t (dB
m)
Pout (dBm) à 12V
Pout (dBm) à 13,8V
U=13.8V
U=12V
P1dBc=55.4 dBm or 348 W
P1dBc=54.5 dBm or 282 W
=TE 1454G=TE 1454G
F5DQK jan 2008, rel 02 34
TE-1452G: Pout versus Pin à 144.400 MHz with driver
47.8
45.8
44.3
42.8
42
40.5
36.7
32.6
I à 13.8V (A)
382
375
370
360
350
330
280
225
13.8V
1801551351
31027524010
32028226015
32530027020
300
262
245
200
12.5V
2301752.5
2802125
3002307.5
332
13V
275
12V
25
Yield%
Pin (W)
- Rig FT-847, Pin from 1 to 25W- Wattmeter Telewave model 44A- Dummy load BIRD Termaline 8135 - 150W- MAAS SPS9600 power supply à 13.8V
F5DQK jan 2008, rel 02 35
TE 1452G with driver at 144,35 MHz: Pout/Pin
100
150
200
250
300
350
400
0 5 10 15 20 25Pin (W)
Pou
t (W
)
30
40
50
60
70
80
90
Pout (W) à 12V
Pout (W) à 12,5V
Pout (W) à 13V
Pout (W) à 13,8V
I (A) à 13,8V
U=13.8V
I (A
mps
)I @ U=13.8V
Original manufacturer version !!
- Max SAFE Pin allowed <25W- Sat Pin 10W !!!!!!
U=12V
F5DQK jan 2008, rel 02 36
QRO 2 meter amps comparaison
0
50
100
150
200
250
300
350
400
0 10 20 30 40 50
Pin (W)
Pou
t (W
)
B-5030-G Pout (W)
HL-350Vdx Pout (W)
TE-1452G Pout (W) without driver
U=13.8V
F5DQK jan 2008, rel 02 37
Aknowledgements-- Special thanks to Jim W3ATV who’d sell me this « technician special » amp, also to many US hams but especially Jeff Allen KB9YSJ from Los Angeles, Dave WB0GAZ, David W3KM, Don N8ECH, KT0WN, John VE3MPH, Maximo EA7FGJ and many others for the precious help I’d get and the veryconstructive discussions we’d have about-- Also to many french hams who kindly’d give me complementary US screws vy difficult to find here in W-Europe !!!-- The AD5TH site also gives many infos about TE Systems six & two meter amps
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