diff --git a/src/include/86box/machine.h b/src/include/86box/machine.h
index b3dc4cdfa..b7702e55b 100644
--- a/src/include/86box/machine.h
+++ b/src/include/86box/machine.h
@@ -569,6 +569,7 @@ extern int             machine_at_acer100t_init(const machine_t *);
 
 /* HT18 */
 extern int             machine_at_ama932j_init(const machine_t *);
+extern int             machine_at_tandy1000rsx_init(const machine_t *);
 
 /* Intel 82335 */
 extern int             machine_at_adi386sx_init(const machine_t *);
diff --git a/src/include/86box/sound.h b/src/include/86box/sound.h
index 71cd65e5a..5cf11bc3c 100644
--- a/src/include/86box/sound.h
+++ b/src/include/86box/sound.h
@@ -245,6 +245,7 @@ extern const device_t soundman_device;
 /* Tandy PSSJ */
 extern const device_t pssj_device;
 extern const device_t pssj_isa_device;
+extern const device_t pssj_1e0_device;
 
 /* Tandy PSG */
 extern const device_t tndy_device;
diff --git a/src/machine/m_at_386sx.c b/src/machine/m_at_386sx.c
index 9ad29e2e8..6b5c4414c 100644
--- a/src/machine/m_at_386sx.c
+++ b/src/machine/m_at_386sx.c
@@ -42,6 +42,7 @@
 #include <86box/vid_cga.h>
 #include <86box/flash.h>
 #include <86box/machine.h>
+#include <86box/sound.h>
 
 /* ISA */
 /*
@@ -369,6 +370,32 @@ machine_at_ama932j_init(const machine_t *model)
     return ret;
 }
 
+int
+machine_at_tandy1000rsx_init(const machine_t *model)
+{
+    int ret;
+
+    ret = bios_load_linear("roms/machines/tandy1000rsx/tandy-1000rsx-1-10.00.bin",
+                           0x000e0000, 131072, 0);
+
+    if (bios_only || !ret)
+        return ret;
+
+    machine_at_common_ide_init(model);
+
+    device_add(&headland_ht18c_device);
+    device_add_params(machine_get_kbc_device(machine), (void *) model->kbc_params);
+    device_add(&pssj_1e0_device);
+
+    if (fdc_current[0] == FDC_INTERNAL)
+        device_add(&fdc_at_device);
+
+    if (gfxcard[0] == VID_INTERNAL)
+        device_add(machine_get_vid_device(machine));
+
+    return ret;
+}
+
 /* Intel 82335 */
 int
 machine_at_adi386sx_init(const machine_t *model)
diff --git a/src/machine/machine_table.c b/src/machine/machine_table.c
index 4b3c22615..c67a22c04 100644
--- a/src/machine/machine_table.c
+++ b/src/machine/machine_table.c
@@ -5511,6 +5511,50 @@ const machine_t machines[] = {
         .snd_device               = NULL,
         .net_device               = NULL
     },
+    /* Has unknown KBC firmware */
+    {
+        .name              = "[HT18] Tandy 1000 RSX",
+        .internal_name     = "tandy1000rsx",
+        .type              = MACHINE_TYPE_386SX,
+        .chipset           = MACHINE_CHIPSET_HT18,
+        .init              = machine_at_tandy1000rsx_init,
+        .p1_handler        = machine_generic_p1_handler,
+        .gpio_handler      = NULL,
+        .available_flag    = MACHINE_AVAILABLE,
+        .gpio_acpi_handler = NULL,
+        .cpu               = {
+            .package     = CPU_PKG_386SX,
+            .block       = CPU_BLOCK_NONE,
+            .min_bus     = 0,
+            .max_bus     = 0,
+            .min_voltage = 0,
+            .max_voltage = 0,
+            .min_multi   = 0,
+            .max_multi   = 0
+        },
+        .bus_flags = MACHINE_PS2,
+        .flags     = MACHINE_IDE | MACHINE_VIDEO | MACHINE_GAMEPORT,
+        .ram       = {
+            .min  = 1024,
+            .max  = 9216,
+            .step = 512
+        },
+        .nvrmask                  = 127,
+        .jumpered_ecp_dma         = 0,
+        .default_jumpered_ecp_dma = -1,
+        .kbc_device               = &kbc_at_device,
+        .kbc_params               = 0x00000000,
+        .kbc_p1                   = 0x000004f0,
+        .gpio                     = 0xffffffff,
+        .gpio_acpi                = 0xffffffff,
+        .device                   = NULL,
+        .kbd_device               = NULL,
+        .fdc_device               = NULL,
+        .sio_device               = NULL,
+        .vid_device               = &gd5402_onboard_device,
+        .snd_device               = NULL,
+        .net_device               = NULL
+    },
     /* Most likely has a Phoenix MultiKey/42 keyboard controller. */
     {
         .name              = "[Intel 82335] ADI 386SX",
diff --git a/src/sound/snd_pssj.c b/src/sound/snd_pssj.c
index 7de8ec824..1b10fdd8d 100644
--- a/src/sound/snd_pssj.c
+++ b/src/sound/snd_pssj.c
@@ -55,8 +55,10 @@ pssj_write(uint16_t port, uint8_t val, void *priv)
             if (!pssj->enable)
                 timer_disable(&pssj->timer_count);
             sn74689_set_extra_divide(&pssj->sn76489, val & 0x40);
-            if (!(val & 8))
+            if (!(val & 8)) {
                 pssj->irq = 0;
+                picintc(1 << 7);
+            }
             pssj_update_irq(pssj);
             break;
         case 1:
@@ -78,7 +80,7 @@ pssj_write(uint16_t port, uint8_t val, void *priv)
             break;
         case 3:
             pssj->freq      = (pssj->freq & 0x0ff) | ((val & 0xf) << 8);
-            pssj->amplitude = val >> 4;
+            pssj->amplitude = (val & 0xef) >> 4;
             break;
 
         default: