Heathkit H19 Information

This document was updated on Monday, 28 March 2005.
Internal changes only; no changes to content.

Warning
There are dangerous voltages inside this unit (up to 15,000 volts). Be very careful when performing the following adjustments. If in doubt, have a qualified professional adjust the unit for you.

Terminal Logic Board Switch Settings

**Switch S401 Sets the Communications Mode**
Switch Section	Heath Mode	Description
0 - 3	4800 or 9600	Baud Rate - Selects any of 12 baud rates from 110 to 9600 baud. (See the Baud Rate Chart below.)
4	No Parity (0)	Parity - Programs the H19 Terminal to generate or eliminate the parity bit. UP (0) = Even Parity DOWN (1) = Odd Parity
5	Even (0)	Odd/Even Parity - Irrelevant if section 4 = 0. UP (0) = Even Parity DOWN (1) = Odd Parity
6	Normal (0)	Normal/Stick Parity - Irrelevant if Switch Section 4 = 0. UP (0) = Normal Parity DOWN (1) = Stick Parity
7	Full Duplex (1)	Full Duplex/Half Duplex UP (0) = Half Duplex DOWN (1) = Full Duplex

**Switch S401 Baud Rate Chart**
Switch Section	Baud Rate
0000	N/A
1000	110
0100	150
1100	300
0010	600
1010	1200
0110	1800
1110	2000
0001	2400
1001	3600
0101	4800
1101	7200
0011	9600

**Switch S402 Sets the Display, Keyboard, and Escape Modes**
Switch Section	Setting	Description
0	Up (0)	Underscore Cursor
0	Down (1)	Block Cursor
1	Up (0)	Key Click
1	Down (1)	No Key Click
2	Up (0)	Discard past end-of-line (no Auto-carry at end of line)
2	Down (1)	Wrap Around (Auto-Carry at end of line)
4	Up (0)	No Auto CR on LF
4	Down (1)	Auto CR on LF
5	Up (0)	Heath Escape Mode
5	Down (1)	ANSI Escape Mode
6	Up (0)	Keypad Normal (Enters numbers when key is pressed.)
6	Down (1)	Keypad Shifted (Enters display manipulation commands when a keypad key is pressed.)
7	Up (0)	60 Hz Display Refresh
7	Down (1)	50 Hz Display Refresh

Video Board Adjustments

The only tools you need to adjust the video board is an alignment tool (such as the Heath part #490-1) and a small screwdriver. Both should be insulated.

In the following, the direction of rotation of all potentiometers is referenced to the rotor side of the control.

With power off, do the following:

Set the OFFLINE and CAPSLOCK keys to their down position.
Set section S2 of S402 on the Terminal Logic circuit board to its logic one position (down) to enable the wrap-around function.

Set the following controls on the Video circuit board to the center of their rotation:
- FOCUS R271
- G1 R268
- HORIZ CENTERING R253
- BRIGHTNESS R216
- VERT SIZE R226
- VERT LINEARITY R228
Apply power to the unit. A cursor or a raster may appear in about 20 to 30 seconds.
Adjust the G1 control (R268) CCW until the raster appears.
If the display is tilted, loosen the yoke clamp screw and rotate the yoke to correct.
Adjust the VERT SIZE control (R226) so the display is about 6 inches high.
Rotate the ring magnets on the back of the yoke to center the display on the screen.
If no cursor is present, adjust the BRIGHTNESS (R216) control CW until the cursor appears.
Press the "Z" or "H" key on the keyboard and the repeat key at the same time until the screen is filled with characters.
Adjust the HORIZ CENTERING control (R253) to obtain a properly centered display.
Adjust the VERT LINEARITY control (R228) so that the top and bottom rows of the characters are of uniform size.
Adjust G1 CW until the raster just disappears.
If the display width is not approximately 8-1/2 inches, adjust the WIDTH COIL (L204) to correct.
Adjust the FOCUS control (R271) for uniform focus across the screen.
Touch-up the above controls as necessary to obtain a good display.
Set section 2 of S402 (on the Terminal Logic circuit board) to it's original position.

Alignment complete.

Go to Bill Wilkinson's Heath Company Page.